
Class : ) 

Book > P L 

Copyright N° ' 



COPYRIGHT DEPOSIT. 



COURSE XV 

BooKlovers Reading Club 

Hand-Book 



mm 



Professor CHARLES A. YOUNG 

Sir Robert S. Ball 

M. Camille Flammarion 

Professor GEORGE C. COMSTOCK 
Professor HAROLD JACOBY 



Jlnd Others 





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ISSUED FROM THE PRESS OF 
THE BOOKLOVERS LIBRARY 
1323 WALNUT ST., PHILADELPHIA 



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THE BOOKLOVERS READING 
CLUB HAND-BOOK TO AC- 
COMPANY THE READING COURSE 
ENTITLED, FIVE WEEKS' STUDT 
OF ASTR0N0M7~ 




SEYMOUR EATON 

Librarian 

FREDERIC W. SPEIRS, Ph.D 

Educational Director 



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THE U8RA3Y OF 

ooMGsers 

Two Copies RsegiVf-O 

DEC. 31 1901 

COPVE?IGHT E*T * ' 

CLASS ^ KXc Mo 
COPY 8. 



Copyright, 1901 
The Booklovess Library 



QttGX 



Jb 



FIVE WEEKS' STUDY 
OF ASTRONOMY 



Course XV: Booklovers Reading Club 



BOOKS SELECTED 

FOR THIS READING COURSE 
by 

Pro CHARLES A. YOUNG 




FIVE WEEKS' STUDY 
OF ASTRONOMY 

TALKS and LECTURES 

by 

Sir ROBERT S. BALL 

and 

M. CAMILLE FLAMMARION 

and 

Professor GEORGE C. COMSTOCK 

and 

Doctor HAROLD JACOBY 

These papers by Sir Robert Ball, M. Flammarion 

and Professor Comstock have been prepared 

especially for readers of this course. 



EDITORIAL NOTES 

by 
Professor WILLIAM J. HOPKINS 




A WORD from THE DIRECTOR 



HERE are many books o?i astronomy 
intended for the general reader, but 
there are few that can \meet successfully 
the test which we applied in making 
the selection for this course. We 
required that the books which we gave 
our readers should be authoritative in 
matter and attractive in presentation. In our 
search for works which would satisfy the double 
standard of scientific spirit and popular form we 
enlisted the aid of Professor Charles A. Toung, 
of Princeton U?iiversity, who by virtue of his 




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A Word from the Director 

investigations of the sun, ranks among the great 
astronomers of the world. Professor Young s 
long experience as a teacher of the science has 
given him an appreciation of the needs of the 
readers for whom this course is specially designed, 
and has ?nade his guidance in the choice of books 
peculiarly valuable. 

The four papers included in the handbook rep- 
resent a most interesting group of astronomers. 
Sir Robert Ball, director of the great observatory 
at Cambridge, England, is equally famous for his 
scientific achievements and his facility in the 
popular presentation of an abstruse science. His 
style is as clear as crystal, and one who reads his 
books does not wonder that he attracted in London 
the largest audience which has ever gathered to 
listen to a lecture on a scientific subject. The 
paper which he has contributed to our handbook is a 
capital illustration of his simple, lucid exposition. 

In striking contrast with the great English 
scientist stands the famous French astronomer, 
C ami lie Flammarion. The differ eiice in person- 
ality and method of thought is clearly reflected in 
the papers of these two notable men as they are 
brought together in this handbook. M. Flamma- 
rion, the poetic popularizer of astronomical sci- 
ence, is regarded by many of his fellow-workers 

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A Word from the Director 

as unsound and visionary in some of his theories, 
particularly those which touch the inhabitants of 
other planets, but the most critical are forced 
to admit that he has done much solid scientific 
work. The enthusiastic plea which he makes 
in his article for the study of astronomy as an 
essential part of the general culture of life is 
thoroughly representative of his point of view. 

Professor Comstock, whG is one of the most 
prominent of the younger astronomers of this 
country, has contributed a paper which is very 
similar in scope and purpose to that of M. Flam- 
marion. The reader will be interested in com- 
paring the articles. Dr. Jacoby, professor of 
astronomy at Columbia, has given directions for 
the construction of a simple piece of apparatus, on 
the theory that "it is always better, in studying 
science, to do something ourselves rather than 
merely talk about the discoveries of others!' 

The reader will find that the suggestions of the 
Topical Outline are very helpful in systematic 
study. Two of the three books cover the general 
subject of astronomy, and the outline indicates the 
most effective method of fitting these two treatises 
together. It also brings the articles and the Illus- 
trative Selections into proper relation with the 
books, and thus unifies the course. 

2L (l 7 ) 



The story to be told leaves the marvels of imagi- 
nation far behind, and requires 710 embellishment 
from literary art or high-flown phrases. Its best 
ornament is unvarnished truthfulness. 

Agnes M. Clerke 



The Idea of the Course 




OR the many persons — perhaps many 
L< thousands of persons — who would know 
more of the wonders of astronomy, but 
can spare neither the time nor the effort 
required in an elaborate system of 
instruction, this reading course has 
been designed. No knowledge can be 
acquired without effort, but it is the aim 
of this course to simplify the subject 
and present it in interesting form. The knowl- 
edge of mathematics required for intelligent read- 
ing is slight, and the reader who has followed 
the suggestions of the handbook will possess 
at the end something worth having. He will 
know the principal stars by name, and will 
understand comets and meteors. He will have a 
reasonably clear idea of the relations of the bodies 
that make up the solar system, and he will be 
able to speak intelligently of the present condi- 
tion of each of the planets and of their probable 
destiny. He should have, also, some familiarity 
with the present state of belief as to the way in 
which our system was formed, and the way in 
which stellar systems different from ours are now 
forming. This in itself is worth while ; and the 
student who would go more deeply into the sub- 
ject will find himself equipped for the task. 



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HINTS AND SUGGESTIONS TO 
THE READER 



The systematic study of any science may be 
undertaken in either of two ways ; observation 
may begin at once and the observations studied 
afterward — this is necessarily the way in which a 
science develops — or the known facts may be 
learned before the observation is begun. Proba- 
bly neither of these methods, in its extreme sense, 
is the better. It is doubtful whether much is to be 
gained by a sudden plunge into observation, 
although there must be some survey of the field 
that is to be covered. The student who confines 
himself to observing will miss much that he should 
see or will be long in seeing it ; and much that he 
does see will have for him no meaning. As 
Serviss says, in one of the books which is before 
you, "Of course, one could sweep over the 
heavens on a starry night and see many interest- 
ing things, but he would soon tire of such aimless 
occupation. The observer must know what he is 
looking at in order to derive any real pleasure or 
satisfaction from the sight." Moreover, little 
or nothing would be gained by any individual 



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The Booklovers Reading Club 

observer in such a way, except, perhaps, some 
notion of the immensity of space and the littleness 
of himself and all that concerned him. That 
mio-ht be worth while. 

It will be best to carry the observations along 
with the study, as far as possible, and it is as- 
sumed that the reader has at the start some 
acquaintance with the heavens — their appearance 
on a fine night, for example, the phases of the 
moon and its motion, differences in brightness of 
stars, the Milky Way, the difference in appear- 
ance of stars and planets. You must have seen 
plenty of meteors or shooting stars, possibly some 
remarkable ones, and you may have seen a comet. 
If you have seen but few of these things, take 
the first opportunity to observe them. Spend as 
much as you will of the first fine evening where 
the view is unobstructed, and absorb all that you 
can of the sight which is spread before you. 
Perhaps you may begin to appreciate dimly the 
immensity of space and the smallness of the part 
our earth plays. In the dark spots between the 
bright stars you will see vaguely a multitude of 
other stars too faint to be seen directly by the 
unaided eye. Do not bother with a glass this 
first time. 

Then take up the three books upon which this 
course is based, and begin the more serious study 
on the following topical plan. 

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TOPICAL OUTLINE 

F THE C U R S E 

i. History — from the earliest records to 
modern times. 
Clerke, Fowler, and Gore, sec. i, chap. i. 

Somewhat similar matter on this topic is contained 
in every text-book on astronomy. 

2. History — the nineteenth century. 
Clerke, Fowler, and Gore, sec. i, chap. n. 

In these two chapters you will meet the names 
of the men who have done most to advance the 
science of astronomy, and other branches of sci- 
ence as well. You should remember the particular 
things for which each is best known and should 
have some idea of the time in which each lived. 
It is hardly worth while to attempt to commit 
dates to memory unless you have a special fond- 
ness for that sort of thing. This topic is very 
broad in scope, for what has been done in the past 
century comes near including all the refinements 
of method and all the discoveries that have con- 
tributed most to our present knowledge of the 
universe, slight as that knowledge is. The reader 
who would become more of a student will do well 
to read carefully Agnes M. Clerke's Popular His- 
tory of Astronomy during the Nineteenth Century, 
listed in the Supplementary Reading. Such a 
study should follow the completion of this course. 

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The Booklovers Reading Club 



3. The Earth and its Rotation. 
Todd, chap. 11. 

Gierke, Fowler, and Gore, sec. 11, chaps. 1, ix, x. 

Some knowledge of the geological history of the 
earth and of the development of life-forms will be 
found interesting. All branches of science are so 
bound together that it is impossible to study one 
branch without wishing to know more of others. 
There is some conflict between geologists and as- 
tronomers as to the earth's age ; the geologists 
needing more time than the astronomers are will- 
ing to give. Probably thestrcncmers have the 
best of it. In this connection read the extract from 
Flammarion's Popidar Astronomy, on page 94 of 
the handbook. 

4. General Aspect of the Heavens; how 
position is defined. 

ServisS) pp. 1-4. 

Todd, chap. v. 

Gierke, Fozvler, and Gore, sec. 11, chap. in. 

The mathematical ideas involved are, for the most 
part, simple. If any difficulty is found with any 
part of this chapter, take a globe and transfer the 
drawings to its surface. A blackened globe is 
best, such as is used in most school rooms, but if 
such a globe is not to be had, an ordinary rubber 
ball will do very well. 

5. Time and its Measurement. 

Gierke, Fozvler, and Gore, sec. n, chap. v. 
Todd, chap. iv. 



Five Weeks' Study of Astronomy 

An interesting account of time distribution 
selected from one of the books recommended by 
Professor Young, Dr. Herbert A. Howe's A 
Study of the Sky, will be found on page 98 of the 
handbook. 

6. The Earth ; its motion. 

Clerke, Fowler, and Gore, sec. 11, chaps. 11, iv. 

7. The Moon and its motions. 
Todd, chap. in. 

Clerke, Fowler, and Gore, sec. 11, chap. vi. 

This is a good place to begin observation. The 
moon is easily observed, even with the naked eye ; 
and with any kind of a glass the character of its 
surface comes out very clearly. Careful examina- 
tion of its surface may be postponed until its his- 
tory is considered under a later topic. Observe 
the moon in its different phases. 

8. Planets and their Satellites. 
Todd, chaps, ix-x. 

Clerke, Fowler, and Gore, sec. 11, chap. vn. 

See if you can pick out a planet with your glass, 
Note the difference between its appearance and 
that of a star. Jupiter shows an evident disk, and 
blazes out like a little moon ; and if the season 
is favorable, you may distinguish the phases of 
Venus. 

9. The Sun. 

Todd, chaps, vi-viii. 

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The Booklovers Reading Club 

Gierke, Fowler, and Gore, sec. n, chap, vni ; 
sec. in, chaps, ii-iii. 

Excellent plates of the sun's surface, showing spots 
and prominences, are to be found in Sir Robert 
Ball's The Story of the Heavens, listed in the Sup- 
plementary Reading. 

10. Tides and their effects. 

Gierke, Foivler, and Gore, sec. n, chap. xiii. 

The action of tides is of great importance and will 
be considered again under later topics. 

ii. Telescopes and other instruments. 
Todd, chap, xviii. 
Gierke, Fowler, and Gore, sec. n, chap, xiv— 

XVII. 

It is well to read over the whole of the reference, 
but for the average student it is not necessary to 
become familiar with all the accessory instru- 
ments. You should get a good idea of the pur- 
pose of each instrument, and should appreciate the 
care and skill required of the astronomer. The 
chapter on telescopes should be studied more care- 
fully. See that you get from this chapter a clear 
idea of the difference between a reflector and a 
refractor, and of the advantages of each. It would 
be a good plan, also, to learn the difference be- 
tween a refracting telescope and an opera-glass ; 
but for this you will have to refer to some modern 
text on physics. The refracting telescope is 
necessarily long, if of high power, unless the most 
modern construction is adopted. By this con- 

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Five Weeks' Study of Astronomy 

struction the telescope is virtually folded upon 
itself, the three sections lying side by side. No 
glass larger than a field-glass is made in this way, 
the highest power being about 12 diameters. In 
the opera glass the eyepiece is concave instead 
of convex, and is placed much nearer to the object- 
glass, so that the length of the instrument is not 
great ; but the field of view is smaller than in the 
other form, which is a disadvantage. 

12. Distances and Dimensions of Heavenly 
Bodies. 

Clerke, Fowler, and Gore, sec. 11, chaps, xi- 

XII. 

For purposes of comparison read the selection on 
this topic from Flammarion's Popular Astronomy 
on page 103 of the handbook. 

13. The Solar System. 
Todd, chap. ix. 

Clerke, Fowler, and Gore, sec. in, chap. 1. 

The attention of the reader is specially directed 
to the admirable statement of the nebular hypoth- 
esis which we have quoted from Agnes M. 
Clerke' s Popular History of Astronomy dnting the 
Nineteenth Century. It appears on page 107 of the 
handbook. 

14. The Terrestrial System. 

Clerke, Fowler, and Gore, sec. in, chap. v. 
Serviss, chap. v. 

Excellent plates of the moon will be found in Sir 
Robert Ball's The Story of the Heavens. They are 

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The Booklovers Reading Club 

from drawings and photographs. Refer to the 
plates in chapter in of Todd's Stars and Telescopes. 
Read Sir Robert Ball's paper contributed to this 
course, The Moons Story; and also Professor 
H olden' s The Birth and Death of the Moon, in 
Harper s Magazine for August, 1901, if that is 
available. The article contains some fine photo- 
graphs made at the Lick Observatory. 
The history of the earth and the moon, so far as 
we can guess at it, shows an example of the action 
of tides on a great scale. The result, however, is 
somewhat different from that in the case of any 
other planet, as will appear on further study. 
Follow the text of Serviss, chapter v, in your ob- 
servations. If you have any difficulty, it is likely 
to be a lack of steadiness in holding the glass. This 
is not so troublesome in the case of the moon as it 
will be when you begin on the stars and planets, 
and the difficulty will be about in proportion to 
the power of your glass. An opera-glass with a 
power of about 4 does very well, and if you have a 
field-glass besides, with a power anywhere from 7 
to 12, you will see much more than you can see 
with the opera-glass. If the lack of steadiness is 
found to be troublesome, the difficulty may be 
remedied in a simple way. In observing the stars, 
some such device as that recommended in the 
next paragraph will be found almost necessary 
for most observers. 

Having selected the best available spot for observ- 
ing — an open field is best, but a skylight or even 
an upper window will do — arrange a support for 
your glass. If the place is a window, the support 
may be fastened at the edge, either inside or out- 
side. If the field is selected, drive a stake and 

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Five Weeks' Study of Astronomy 

at a convenient height fasten a cross-piece by a 
single screw. The screw may be tightened until 
the cross piece will just turn upon it, but will stay 
in any position in which it is put. The glass may 
be clamped or tied on this cross piece. It would 
not be a difficult matter to set the screw nearly in 
the polar axis, so that the mounting should be 
roughly equatorial ; and the addition of another 
cross-piece fastened by a screw to the top of the 
first, as the first is to the stake, would make the 
mounting complete. These arrangements are not 
necessary, but they will be found convenient, and 
they are easily made. The height may be suited 
to the observer, either standing or sitting. 
In all observations it will be a help to have a 
note-book at hand. Anything of interest should 
be recorded. 

15. The Inner Planets : Mercury and 
Venus. 

Todd, pp. 1 04- 1 10. 

Clerke, Fowler, and Gore, sec. in, chap. iv. 

Serviss, p. 139. 

16. Mars. 

Todd, p. in; chap. xi. 

Clerke, Fowler, and Gore, sec. in, chap. vi. 

Serviss, p. 140. 

17. The Outer Planets. 
Todd, pp. 1 1 1- 1 47. 

Clerke, Fowler, and Gore, sec. in, chaps, vi, 
VIII, ix, x. 



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The Booklovers Reading Club 



i 8. Comets and Meteors. 
Todd y chaps, xii-xiv. 
Clerke, Fowler, and Gore, sec. in, chaps, xi- 

XIII. 

The accounts of famous comets are of interest, but 
it is hardly to be expected that the reader will re- 
member the details. Not very much is known with 
certainty about the tails of comets, but a comet 
certainly wastes its substance at a great rate every 
time it approaches the sun, which accounts for the 
used up appearance of the planetary comets. The 
connection between comets and meteors is pretty 
well established, and the periodic showers of 
meteors are supposed to be "the debris of ancient, 
but now disintegrated comets, whose matter has 
become distributed round their orbits." In this 
connection it is interesting to note that the great 
shower of the Leonid meteors expected in 1899 or 
1900 has, so far, failed to keep its appointment, 
probably because of the disturbance made by one 
of the outer planets. It is supposed that the comet 
from which these meteors are derived was intro- 
duced into our system by Uranus in 126 A. D. 

19. Stars and Constellations. 
Todd y chaps, xv, xvn. 
Clerke, Fowler, and Gore, sec. iv, chaps, i-vi. 

A mere reading of descriptions of the stars and 
their positions is of little value. Observation 
should accompany the reading ; and for that it will 
be best to follow Astronomy with an Opera-Glass. 
The order of work will depend on the season. 
What an observer will get from such work will de- 

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Five Weeks' Study of Astronomy 

pend on himself. There is scarcely a limit to the 
extent to which it can be carried, but at least you 
should be able to recognize the brightest stars and 
should know the places of the familiar constella- 
tions. If you can find some double stars and the 
conspicuous clusters and nebulae, so much the 
better, 

20. The Cosmogony : Life and Death of 
Stars and Planets. 

Todd, chap. xvi. 

Other matter bearing upon this subject is con- 
tained in the references already given, but so scat- 
tered through them that it is impossible to refer to 
it specifically. 

2 1 . Structure of the Visible Universe. 
Clerke, Fowler, and Goi'e, sec. iv, chap. vn. 



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Astronomy as a Culture 
Study: A Ten-Minute Talk 

by GEORGE C. COMSTOCK 



3L (33) 



Astronomy as a Culture 
Study : A Ten-Minute Talk 

by GEORGE C. COMSTOCK 



Professor George Cary Comstock, although 
of New England stock, was born in Wisconsin 
and has spent most of his life in the Mississippi 
Valley and the region of the Great Lakes. Dur- 
ing his student years at the University of Michi- 
gan, and for a short time thereafter, he was 
engaged in field work under the Corps of Engi- 
neers, U. S. A. He served successively as an 
assistant in the observatories at Ann Arbor and 
Madison, and was for a time engaged upon astro- 
nomical calculations in the Nautical Almanac 
office at Washington. During this period he also 
pursued the study of law and was admitted to the 
bar, but never engaged in practice. After serv- 
ing for two years as professor of mathematics 
and astronomy in the Ohio State University, he 
was called to the professorship of astronomy in 
the University of Wisconsin and the directorship 
of the Washburn Observatory, which position he 
still holds. He is secretary of the Astronomical 
and Astrophysical Society of America. His 
published works include a treatise upon the 
Method of Least Squares, a Text-book of Astron- 
omy, five volumes of the Washburn Observa- 
tory publications, and numerous scientific papers 
scattered through the periodical literature of 
astronomy. 

Modern life depends for its very existence 
upon the physical and natural sciences, 
whose applications are so closely twined into its 
warp and woof that not the pattern only but the 

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The Booklovers Reading Club 



fabric's very substance must be destroyed by 
their elimination. On the material side, food and 
raiment, shelter and transportation are among 
their indispensable contributions to human wel- 
fare ; and if things moral, intellectual, and social 
are in their substance less closely bound to the 
sciences, they are, at least, disseminated and 
brought home to mankind through the same 
agencies that minister to its material needs. Each 
of the great sciences has its especial relation to the 
practical affairs of 4ife, and astronomy stands 
amonor them with its aid to navigation and com- 
merce, and with its study of the sun, the fountain- 
head of all terrestrial energies. But it is with 
quite a different phase of the science that we are 
here concerned — its culture side, its capacity for 
bringing into human lives, which perforce run in 
artificial channels, the joy of contact with nature 
and knowledge of God's way in nature. And, in 
sooth, astronomy possesses such a culture side, 
singularly accessible and singularly attractive to 
whoever will seek it at first hand and will study 
the heavens themselves, using books as a guide 
but not as a substitute for nature. 

One need not wonder that astronomy is the 
oldest of the sciences, that prehistoric man pos- 
sessed and transmitted to us through his poster- 
ity a knowledge of the sky that, though crude and 
limited, was in substance more accurate and more 
complete than his knowledge of the earth and its 



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Five Weeks' Study of Astronomy 



complexity. Despite their far-off air of mystery, 
stars are simpler than stones or plants or animals, 
and by their beauty challenge an attention oft 
denied to meaner things ; so that a knowledge of 
the stars grew up in the dawn of civilization be- 
cause they presented problems essentially simple 
to minds convinced that these same problems 
were immensely important. Egyptian and Chal- 
dean, priest and astronomer, alike believed that 
the issues of life were determined in the heavens, 
that the course of human events might be pre- 
dicted from the stars ; and in this practical and 
often sordid spirit the stars and their courses 
have been studied even to our own day, for the 
belief in astrology is not yet quite extinct, al- 
though Kepler, three centuries ago, was probably 
the last astronomer of eminence to cast horo- 
scopes for a living and to argue with his con- 
science over the right and wrong of such a 
practice. 

But the occult element has faded from the sky, 
and to the modern student the stars are a part of 
nature, governed by the same physical and chem- 
ical laws that rule the earth, and challenging his 
interest as a part of nature on an even footing 
with flower or feather, fin or fur. But which of 
these can rival the sky as a subject of contempla- 
tion and study for a mind absorbed chiefly by 
the daily cares of life, from which it turns for rest 
and recreation, for the joy, and uplifting, and 



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The Booklovers Reading Club 

inspiration that come from nature's own hand? 
Flowers and foliage are, for the most part, limited 
to one season of the year, while the stars shine 
winter and summer alike. Birds and animals 
must be sought in their appropriate haunts, while 
the heavens need no expedition for their search, 
but stand open to view alike from the crowded 
city roof-tops and from the loneliest camp-fire of 
Alaskan wilds. Nor do the stars call for any 
special apparatus to charm forth their attractive- 
ness — telescope, or camera, or spectroscope. 
Often in the wakeful hours of midnight travel has 
the writer of these lines found pleasure and repose 
in lifting the curtain of his car window to look 
upon and admire celestial friends whisked into 
sight and out again as a winding track changed 
rapidly the point of view. 

" Why did not some one teach me the constel- 
lations in my youth ? " cried Carlyle, and a greater 
philosopher than he, who did thus learn them, 
proclaims that two things alone awake in his mind 
a sense of awe — God's moral order and the starry 
skies. Once made familiar, the sky is a life-long 
source of joy ; but it must be learned, learned by 
heart, as the children say, for most men grow up 
with small appreciation of its charm, so that, in the 
language of old Gobbo, they are sand-blind to its 
beauty, high-gravel blind to its wealth of changing 
aspects. 

Do you know from your own experience that 

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Five Weeks' Study of Astronomy 



the sky turns round, that the stars rise and set 
like the sun and moon ? Many a man who has 
lived beneath them for half a lifetime has not 
learned so much. Do you know that the stars of 
the winter sky are not the stars of summer, and 
have you watched the procession of the constella- 
tions through which this change is made ? Have 
you seen in the spring time Orion and his follow- 
ers, the big dog, Canis Major, and the little dog, 
Canis Minor, glide each night a little earlier 
down the western sky until, with the advancing 
season, they are lost in the twilight and replaced 
by the Lion and the Maid, Leo and Virgo, who 
usher in the summer, and by the Scorpion and 
Hercules, who proclaim the fulness of the mid- 
year? Long before the invention of almanacs 
and calendars mankind relied upon such signs as 
these for the coming of seed time and harvest ; 
and is it pure gain that in their place there has 
been set up the patent medicine counselor and 
the insurance manual of times and seasons ? 

You have seen the moon sweep majestically 
across the sky through half a dozen constellations 
in a fortnight, but have you watched the slower 
pace and the serener beauty of a planet that, like 
Venus, creeps modestly forth from the glare of 
sunset and night by night, month after month, 
grows in brilliancy until it stands as a celestial 
beacon commanding even the most heedless eye 
and stirring even the dullest churl to admiration 



(39) 



The Booklovers Reading Clu 



of its splendor ? A glorious spectacle and worthy 
to be followed even in its declining course as, 
with diminishing brightness, the planet moves 
back toward the sun, setting each night a little 
earlier until it is lost in the sun's radiance, only to 
reappear a little later in the morning sky, there 
to run another course. Or follow Jupiter which, 
in these early years of the twentieth century, is 
the brilliant ornament of the midnight sky of 
summer, rising and setting with the fainter stars 
about him, but also with a motion of his own, 
drifting through the constellations slowly but 
steadily, so that even the unaided eye may detect 
his motion after a few nights of careful watching. 
And so may Mars and Saturn be followed and 
the paths marked out in which they move, a long 
stride toward the east, followed by a shorter one 
to the west, and again a long one to the east 
in endless succession, easy to understand in its 
general character but puzzling in the highest 
degree to many a generation of baffled astrono- 
mers who sought to explain its every feature and 
to foretell the planet's course. Patience and a 
keen eye will secure many a glimpse of Mercury, 
though the tradition runs that, in the more north- 
ern latitude of Poland, to the very end of his long 
life Copernicus sought it in vain. Even Uranus 
comes within the range of naked eye vision, as 
with slow pace it picks its way among the constel- 
lations of the zodiac, unseen by a hundred genera- 
te) 



Five Weeks' Study of Astronomy 

tions of astronomers until detected little more 
than a century ago by the telescope of Herschel. 
A striking witness, through its present visibility, 
that the known thing is easier seen than the 
unknown, though both be equally bright. 

And the stars themselves, fixed stars, that, 
unlike the planets, abide ever in the same constel- 
lations, forming among themselves indissoluble 
groups and families that come and go, each at its 
appropriate season, with an unrivaled punctuality 
that regulates the clocks and watches of mankind 
today as five thousand years ago the same stars, 
moving at the same unvarying pace, regulated the 
lives of men to whom clocks and watches were 
unimagined things. Are not these admirable for 
their well ordered beauty and their changeless 
duration ? Orion and the Pleiades, the Great Bear, 
the Scorpion, the Sickle and that glorious celes- 
tial girdle of shimmering light that men call the 
Galaxy, or Milky Way — these have come to us 
substantially unchanged from the days of David 
and Homer, of Job and the earliest civilization 
that grew up in the valley of the Nile. And what 
else is there of such undoubted antiquity and so 
easily accessible to modern eyes ? Where else 
in art or nature shall we find the veritable objects 
about which twine more than half a hundred cen- 
turies of admiring myth and legend, of reverent 
worship, and of coldly scientific study? The 
glorious, the immutable, the eternal stand here as 

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nowhere else, revealed to whatsoever eye will 
look upon them, to whatsoever mind will contem- 
plate them and drink in their lessons at first 
hand. 

But, in very sooth, even the stars are not im- 
mortal. The hand of time is upon them working 
slowly, so slowly that literally "a thousand years 
are but as a day when it is past," but working so 
surely that we may not doubt that even the celes- 
tial hosts shall pass away. 

" The cloud-capp'd towers, the gorgeous palaces, 
The solemn temples, the great globe itself, 
Yea, all which it inherit, shall dissolve, 
And, like this insubstantial pageant faded, 
Leave not a rack behind." 

Would you behold the transitoriness of even 
the heavenly bodies, the passing away of things 
that come not back again, then look into the early 
morning sky of August and behold the shooting 
stars that for a moment dash across the firma- 
ment and then are lost forever. So flagrant is 
their contrast with the abiding stars that many a 
generation of men refused to believe them of 
celestial origin, and in the quaint church legends 
of the olden time they are christened "the fiery 
tears of St. Laurence," after the patron saint of 
the day upon which they are wont to appear. 
But these tears fall from the sky not on St. Lau- 
rence's day alone ; though less abundant, they 
may be seen by the patient observer on any clear 

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Five Weeks' Study of Astronomy 

and moonless night, and he who has once seen 
them, counted their number and watched their 
paths gleaming like a rocket's trail, will turn to 
the astronomer and his books, seeking an ex- 
planation of this celestial bombardment with a 
pleasure and interest unknown to the student of 
books alone. 

But shooting stars are not the only transient 
features of the sky ; their brother, the fire-ball, 
and their cousin, the comet, are by no means in- 
frequent visitors, always sure of a welcome from 
the ubiquitous reporter whose published account 
of and guidance to them would oftentime prove 
more valuable had his eyes learned to know the 
sky before his victims' arrival. Of even greater 
interest and moment than these chance visitors is 
the blazing forth in a night of a temporary star, 
such as that of February, 1901, which, unheralded 
and unexpected, rose in a few hours from com- 
plete invisibility to be the rival of the brightest 
stars in the sky, and then slowly died away, its 
decline extending over many months. This is no 
birth of a new star, as it is sometimes called, but 
the fiery transformation of an old one, perchance 
long since extinct and cold, into something new — 
a tremendous catastrophe like that foreshadowed 
in the stirring words of the Dies Irce, whose elo- 
quent Latin, Solve t scedum in favilla, is feebly 
rendered by the English words, " By fire shall the 
world be tried." 



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The study of the sky and its brilliant throng of 
twinkling lights is not primarily a matter of tele- 
scopes, of observatories, and of a class of men set 
apart for it alone. Like faith, hope, and charity, 
the heavens and their culture stand open to the 
layman without intervention of either priest or 
astronomer, although each of these, if true to his 
vocation, may do much to aid, and guide, and 
instruct his fellow-men. A simple star-map and, 
it may be, an opera-glass, a clear sky, and an 
active mind are all the equipment really required 
for the culture study that we have in mind. 
A well chosen book or two will save much time 
and some vexation by suggestions of where to 
look, what to see, and what to do, much as the 
catalogue may serve as guide to a picture gal- 
lery ; but who would wish his guide-book to be a 
substitute for the pictures, or his text-book to 
supplant the heavens as a subject of study? 
Beware of these, for 'twas of such the greatest of 
English poets wrote : 

" Small have continual plodders ever won 
Save base authority from others' books. 
These earthly godfathers of heaven's lights 
That give a name to every fixed star 
Have no more profit of their shining nights 
Than those that walk and wot not what they are." 




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The Moon's Story: A 

Lecture by sir Robert ball 



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The Moon's Story: A 

Lecture by sir Robert ball 



Sir Robert Stawell Ball is the eldest son of 
the late Robert Ball, a distinguished naturalist 
and author. After his graduation from Trinity 
College, and a novitiate as astronomer to the 
Earl of Rosse, he held chairs in the Royal College 
of Science for Ireland, and in the Universities of 
Dublin and Cambridge. He relinquished the 
office of Royal Astronomer of Ireland to become 
director of the Cambridge Observatory. Sir Rob- 
ert Ball has lectured before leading institutions 
of the United Kingdom, and his papers on mathe- 
matics and physics have appeared constantly dur- 
ing the last twenty years. His recent publica- 
tions include The Story of the Sun, The Story of 
the Heavens, In the High Heavens, and Great 
Astronomers. His last extensive work, A Trea- 
tise on the Theory of Screws, appeared in 1900. 
Frequent honors have come to him. He received 
the Cunningham gold medal of the Irish Academy 
for a series of memoirs on dynamics ; he has held 
the presidency of the Royal Zoological and Royal 
Astronomical Societies and of the Mathematical 
Association, and in 1886 he was created a knight 
of the realm. 



I think there is no chapter in modern science 
more remarkable than that which I here pro- 
pose to describe. It has, indeed, all the elements 
of a romance. I am to sketch an event of the 
very greatest moment in the history of this uni- 
verse, which occurred at a period of the most 

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extreme antiquity, and has been discovered in the 
most remarkable manner. 

The period of which I write is far more ancient 
than that of the pyramids of Egypt or of any other 
monuments erected by human effort. It is even 
more early than that very remote time, hundreds 
of thousands of years ago, when man himself first 
came upon this globe. Our retrospect has to 
pierce right through those vastly protracted cycles 
which the geologists have opened up to us. We 
speak of a period long anterior to the ages during 
which our continents were being sculptured into 
their present mountain chains and river courses. 
We have to look through those periods still ear- 
lier when great animals, now long extinct, flour- 
ished on this earth. The time of which I write is 
more remote than that very remarkable epoch in 
earth history during which the great coal forests 
flourished. It is earlier than the supreme moment, 
countless millions of years ago, when living or- 
ganisms first became inhabitants of this globe. 
Even here, however, our retrospect must not stop. 
We have yet once more to look back through 
certain anterior periods to a time when our earth 
was in its earliest youth. The chapter of history 
about which I am now writing is, indeed, in the 
very dawn of things terrestrial. 

It might be thought that it would be utterly im- 
possible for us to learn anything with regard to 
what took place at a time so immeasurably ante- 

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Five Weeks' Study of Astronomy 

rior to all sources of tradition, and, indeed, to all 
the ordinary channels for obtaining knowledge 
by observation. It fortunately happens, however, 
that the darkness of this early period is illumined 
by a bright and steady source of light which will 
never deceive us if only we will follow it prop- 
erly. Our trustworthy guide is to be the pen of 
the mathematician, for it is well known that, un- 
less we are going to dispute the fundamental 
proposition that two and two make four, we can- 
not impugn the truths which mathematics dis- 
close. This science knows no boundaries of 
space. It recognizes no limits in time. It is ever 
ready for discussing operations which take place, 
either in the millionth part of a second, or in the 
lapse of uncounted millions of centuries. The 
processes of mathematics are alike available for 
tracing out the delicate movements in the interior 
of a molecule not one-millionth part of the size of 
a grain of sand, or for investigating the proper- 
ties of space so vast that the whole solar system 
occupies only an inconsiderable point by compar- 
ison. Let us, therefore, see what this infallible 
guide has to teach us with regard to that momen- 
tous epoch in the history of our system when the 
moon was born. 

Our argument proceeds from an extremely 
simple and familiar matter. / Every one who has 
ever been on the sea-shore knows the daily ebb 
and flow of the waters, which we call the tides. 

4 L (49) 



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Long ere the true nature of the forces by which 
the moon acts upon the sea was understood, the 
fact that there was a connection between the tides 
and the moon had become certainly known. In- 
deed, the daily observation of a fisherman, or of 
any one whose business was concerned with the 
great deep, would have taught him that the time 
of high water and the time of full moon stood at 
each place in a certain definite relation. The 
fisherman might not have understood the precise 
influence of the moon upon the tides, but if he 
had observed, as he might in some places, that 
when the moon was full the tide was high at 
ten o'clock in the morning, it would be perfectly 
obvious to him that the moon had some special 
relation to this ebbing and flowing of the ocean. 
Indeed, we are told of some savage race who, 
recognizing that the moon and the tides must be 
associated, were still in some considerable doubt 
as to whether it was the moon which was the 
cause of the tides or the tides which were the 
cause of the moon. 

The ebbing and flowing of the tide opens up 
this chapter in remote history, which we can now 
explore mainly by the help of the researches of 
Professor George Darwin. For as the tides 
course backward and forward, sweeping to and 
fro vast volumes of water, it is obvious that the 
tides must be doing work. In fact, in some places 
they have been made to do useful work. If 

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Five Weeks' Study of Astronomy 

the water as it rises be impounded in a large res- 
ervoir, it can be made to turn a water-wheel as it 
enters, while another water-wheel can be driven 
as the reservoir empties itself a few hours later. 
Thus we produce a tidal mill It is quite true 
that so long as coal remains tolerably cheap and 
steam power is consequently readily available, 
it is not often possible to employ the direct power 
of the tides in an economical manner. For our 
purpose it is merely necessary to note that, day 
after day, week after week, year after year, the 
tides must be incessantly doing work of some 
kind or other. 

Every practical man knows that a certain quan- 
tity of work can be done only by the expenditure 
of a certain quantity of energy. He also knows 
that there is in nature no such thing as the crea- 
tion of energy. It is just as impossible to create 
out of nothing the energy which should lift an 
ounce weight through a single inch as it would be 
to create a loaf of bread out of nothing. If, there- 
fore, the tides are doing work — and we have seen 
that they undoubtedly are doing work — it follows 
that there must be some source of energy on which 
the tides are enabled to draw. A steam engine 
is able to put forth power because of the energy 
developed from the coal which is continually sup- 
plied to the furnace. But where is the equivalent 
of the coal in the great tidal engine ? We might 
at first hazard the supposition that, as the moon 

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is the cause of the tides, so we must look to the 
moon to provide the energy by which the tides 
do their work. This is, however, not exactly the 
case. The match which lights the fire under a 
steam boiler is in one sense, no doubt, the cause 
of the energy developed ; but we do not therefore 
assert that the power of the engine is derived 
from the match. It comes rather from the fuel 
whose consumption is started by the match. In 
like manner, though the moon's attraction causes 
the tides, yet it is not from the moon that the 
tidal energy is drawn. There is only one possi- 
ble source for the energy necessary to sustain the 
tides. Every one who is conversant with mechan- 
ical matters knows the important duty which the 
fly-wheel performs in a mill. The fly-wheel, in 
fact, may be considered as a reservoir into which 
the engine pours the power generated with each 
stroke of the piston, while the machinery in the 
mill draws on this accumulated store of power in 
the fly-wheel. If the engine is stopped, the fly- 
wheel may yet give a turn or two, for the energy 
which it contains may be still sufficient to drive 
the machinery of the mill for a few seconds. 
But the store of energy in the fly-wheel would 
necessarily become speedily exhausted and the 
fly-wheel come to rest unless it were continually 
replenished by the action of the engine. 

The earth may be regarded as a mighty fly- 
wheel which contains a prodigious store of 



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Five Weeks' Study of Astronomy 

energy. That energy is, however, never added to, 
for there is no engine available. If, however, no 
energy were withdrawn from the earth, then the 
globe would continue to spin round its axis once 
every twenty-four hours forever. As, however, 
the tides need energy to get through their work, 
they abstract what they require from the store 
which they find at hand in the rotation of the 
earth. Next time you see the tides scouring up 
and down a river, you may reflect that the power 
which impels that mass of water to and fro has 
been obtained solely at the expense of the spin- 
ning of our globe. Indeed, the little child who 
digs a moat in the sand, which is filled by the 
rising tide, affects to a certain extent the revolu- 
tion of this earth about its axis. 

This withdrawal of energy from the earth is in- 
cessantly taking place along almost every coast. 
From day to day, from century to century, from 
eon to eon, energy is daily being withdrawn and 
daily wasted, never again to be restored. As the 
earth has no other means of replenishing its 
stores, the consequence is inevitable. The quan- 
tity of energy due to the rotation of the earth 
must be gradually declining. Stated in this way 
perhaps the intimation is not very alarming, but 
placed in other words, the results at which we 
have arrived assume the more practical expres- 
sion that the tides must be gradually checking the 
speed with which the earth turns round. The 

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tides must, in fact, be increasing the length of the 
day. In consequence of the tides which ripple 
to and fro on our shores and which flow in and 
flow out of our estuaries and rivers, today is 
longer than yesterday, and yesterday was longer 
than the day before. I may, however, admit at 
once that the change thus produced is not very 
appreciable when only moderate periods of time 
are considered. Indeed, the alteration in the 
length of the day from this cause amounts to no 
more than a fraction of a second in a period of a 
thousand years. Even in the lapse of ordinary 
history there is no recognizable change in the 
length of the day. But the importance of our 
argument is hardly affected by the circumstance 
that the rate at which the day is lengthening is a 
very slow one. The really significant point is that 
this change is always taking place and lies always 
in the same direction. It is this latter circum- 
stance which gives to the present doctrine its 
great importance as a factor in the development 
of the earth-moon system. We are accustomed 
in astronomy to reason about movements which 
advance for vast periods in one direction, and 
then become reversed. Such movements as these 
are, however, not the real architects of the uni- 
verse, for that which is done during one cycle of 
years is undone during the next. But the tides 
are ever in operation, and their influence tends 
ever in the same direction. Consequently the 

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Five Weeks' Study of Astronomy 

alteration in the length of the clay is continually 
in progress, and in the course of illimitable ages 
its effects accumulate to a startling magnitude. 

The earth now revolves on its axis once in 
twenty-four hours. There was a time, millions of 
years ago very likely, when it revolved once in 
twenty-three hours. Earlier still it must have 
spun on its axis in twenty-two hours, while this 
succeeded a time when the day was only twenty 
hours. The very same arguments applied in 
those times which apply at the present, so that if 
we strain our vision back into the excessively re- 
mote past, we find the earth spinning ever more 
and more rapidly, until at last we discern an 
epoch when the length of the day, having de- 
clined to eight hours and seven hours, had at last 
sunk to something like five or six hours. This is 
the time when the moon's story commences. At 
this eventful period the earth accomplished about 
four revolutions in the same time that it now re- 
quires for a single one. We do not attempt to 
assign the antiquity of this critical moment. It 
must certainly have been far earlier than the time 
when this earth became fitted for the reception of 
organized life. It must have been, at least, many 
millions of years ago. If it be thought that the 
vagueness of our chronology is rather unsatisfac- 
tory, then it must be remembered that even his- 
torians, who have human records and monuments 
to guide them, are still often in utter uncertainty 

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The Booklovers Reading Club 

as to the periods during which mighty empires 
flourished or as to the dates at which great dynas- 
ties rose or perished. 

But our story has another side to it. Among 
the profoundest laws of nature is that which 
asserts that action and reaction are equal and 
opposite. We have seen that the moon is the 
cause of the tides, and we have further seen that 
tides act as a brake to check the speed with 
which the earth is rotating. This is the action of 
the moon upon the earth, and now let us consider 
the reaction with which this action must be inevi- 
tably accompanied. In our ordinary experience 
we observe that a man who is annoyed by another 
feels an unregenerate impulse to push the annoy- 
ing agent away as far as possible. This is ex- 
actly the form which the reaction of the earth 
assumes. It is annoyed by the moon, and ac- 
cordingly it strives to push the moon away. Just 
as the moon by its action on the earth through 
the medium of the tides tends to check the speed 
with which the earth is rotating on its axis, so the 
earth reacts on the moon and compels the satel- 
lite to adopt a continuous retreat. The moon is, 
therefore, gradually receding. It is further from 
the earth today than it was yesterday ; it will be 
further tomorrow than it is today. The process 
is never reversed ; it never even ceases. The 
consequence is a continuous growth in the size of 
the track which the moon describes around the 



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Five Weeks' Study of Astronomy 



earth. It is quite true that this growth is a slow 
one ; so, too, the growth of the oak is impercept- 
ible from day to day, though in the lapse of cen- 
turies the tree attains a magnificent stature. The 
enlargement of the moon's orbit, though imper- 
ceptible from month to month, or even from cen- 
tury to century, has revolutionized our system in 
the lapse of many millions of years. 

Looking back through the mists of time we see 
the moon ever drawing nearer and nearer to the 
earth. Our satellite now revolves at a distance 
of 240,000 miles, but there was a time when that 
distance was no more than 200,000 miles. There 
was a time, millions of years ago, no doubt, when 
the moon was but 100,000 miles away ; and as we 
look further and further back we see the moon 
ever drawing closer and closer to the earth, until 
at last we discern the critical period in earth- 
moon history when our globe was spinning round 
in a period of about five or six hours. The moon, 
instead of revolving where we now find it, was 
then actually close to the earth ; earlier still it 
was, in fact, touching our globe, and the moon 
and the earth were revolving each around the 
other, like a foot-ball and a tennis-ball actually 
fastened together. 

It is impossible to resist taking one step fur- 
ther. We know that the earth was, at that early 
period, a soft molten mass of matter, spinning 
round rapidly. The speed seems to have been 



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so great that a rupture took place, a portion of 
the molten matter broke away from the parent 
globe, and the fragments coalesced into a small 
globe. That the moon was thus born of our earth 
uncounted millions of years ago is the lesson 
which mathematics declares it learns from the 
murmur of the tides. 



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The Charm and Utility of 
Astronomy : A Lecture by 

CAMILLE FLAM MARION 



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The Charm and Utility of 
Astronomy : A Lecture by 

CAMILLE FLAMMARION 



Camille Flammarion was intended by his par- 
ents for the church and was educated in Jesuit 
seminaries. From childhood, however, he was 
fascinated with astronomy and determined to de- 
vote his life to science. At sixteen he published 
a book entitled The Cosmogony of the Ufiiverse. 
This volume was followed three years later (1862} 
by The Plurality of the Inhabited Worlds, the book 
which immediately made his reputation. Since 
then he has done much to popularize the science 
of astronomy by presenting facts in a poetical, 
picturesque, and easily comprehended form. Most 
notable among his popular works are The Marvels 
of the Heavens, The Atmosphere, Urania, Popular 
Astronomy, and Lumen. He has also translated 
several books and has edited the Astronomical 
Encyclopaedia. The creation of the Monthly 
Review of Astronomy, the founding of the Astro- 
nomical Society of France, and the establishment 
of the observatory at Juvisy, his summer home, 
M. Flammarion considers his three greatest 
achievements. 

Is man by nature an intelligent being ? Is he 
endowed with reason ? Is he moral ? Does 
he represent a really superior intellectual species ? 
These are questions which scholars, moralists, and 
philosophers constantly ask. There are many 
answers, uncertain and disputable because man- 
kind comprises all — the good and the bad, the wise 
and the foolish, minds which discern correctly and 

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others whose powers of observation are faulty. 
I The astronomer, being led by his habits of study 
to judge things and beings as a whole from a high 
and remote standpoint and to live a life of 
abstraction, feels that upon this planet we are far 
from the absolute ; that our valuations, our judg- 
ments, depend upon the imperfect, relative, 'and 
often erroneous impressions of our senses ; and 
that from the very nature of our world, the human 
species is far from perfect. But that which 
especially impresses and constantly surprises him 
is that up. to this time most of the inhabitants 
of this world have lived without knowing where 
they were, and without suspecting the wonders 
of the universe. We are indeed surrounded by 
wonders, yet we live blindly upon the earth like 
plants and mollusks. 

It is not uncommon to hear people of the better 
class, otherwise bright and intelligent, ask, " What 
is the good of astronomy ? " It is a little like ask- 
ing of what good are music, painting, physics, of 
what good are all the arts and sciences ; but it is 
less excusable, for astronomy is not only a science, 
it is preeminently the science, the one which 
teaches us about the universe in which we live. 
Without this science we should be in a state of 
deplorable ignorance. 

In many ways we unconsciously make use of 
astronomy. If we but ask the day of the month, 
we put an astronomical question, for we owe 

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Five Weeks' Study of Astronomy 

to this science our calendar, and, therefore, the 
basis necessary for recorded history. Do we 
glance at a watch ? Again it is a matter of astron- 
omy, for time is reckoned by the diurnal move- 
ment of our planet upon its axis, and by the sun's 
crossing certain meridians. Do we drink coffee ? 
Let us remember that if coffee-drinking has be- 
come a habit, it is so not only because the bean 
could from the first be transported at a low price, 
but also because nautical science, which directs 
the course of ships by determining longitude, 
drew its knowledge from observation of the 
eclipses of Jupiter's satellites. For that matter 
navigation could not exist without astronomy. 

It would be difficult to name a subject with which 
astronomy is not associated. Is champagne 
served at the end of a meal ? It is bottled sun- 
shine. Do we taste fruit, inhale a flower's fra- 
grance, admire a field of wheat, or feel the warmth 
from the hearth ? All these are from the store- 
house of the sun. It is the sun that clothes the 
trees and flowers. It is the sun that sings in the 
throats of birds and blooms in the lilacs and 
roses, that gives joy and beauty to nature. It is 
the sun that breathes in the fragrant wind from 
the woods and the meadows enameled with flow- 
ers, that babbles in the brook, that glows in the 
splendor of twilight or the soft gleam of dawn. If 
we travel by train we utilize solar rays which have 
been stored in coal. If we eat, it is of the carbon 

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hoarded by the sun in the field and in the cattle. 
If we climb a glacier or take in our hands a piece 
of the ice itself, we behold the sun's work, for 
without aqueous vapor there can be no ice ; and 
without the sun, no aqueous vapor) 

SHow does it happen that citizens of the earth 
live thus, strangers to this science of the uni- 
verse, knowing so little about the heavenly body 
they inhabit, when nothing in the world is so in- 
teresting as the study of nature ! It is probably 
not so with the inhabitants of the other globes ; 
in that case the infinite universe would be peopled 
by beings not knowing even where they are. 
Surely, if we know neither the heat-giving nature 
of the sun, nor the position of our planet in the 
solar system, nor the reason for the change of 
day and night, of seasons, of years, we are like 
the blind, and can have but vague, narrow, incor- 
rect and imperfect ideas in regard to creation. 
Astronomy concerns us much more closely than is 
generally believed. Not only is it the foremost 
of the sciences, but at least an elementary 
knowledge of it is necessary to any education 
which aims to be thorough, complete, integral, 
rational. 

' Indeed, without astronomy we should have 
but inaccurate and mistaken ideas about many 
things, because we should accept the relative for 
the absolute. This was so in bygone days, when 
the earth represented the entire universe, when 

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Five Weeks' Study of Astronomy 

the traditional conception of creation made people 
believe that sun, moon, and stars had been cre- 
ated for us, and that our earthly abode was the 
only world in existence. Still more childish and 
narrow would be our view were the sky, for in- 
stance, entirely hidden from us. Let us imagine 
for a moment that clouds, instead of forming at a 
certain altitude and being ephemeral, formed on 
the surface of the earth and were permanent. 
Mankind would live in the heart of a perpetual 
fog. We should never see the sun, or the moon, 
or the stars. The succession of day upon night 
would follow without any apparent, well-defined 
cause. It would be impossible to ascertain the 
shape of the terrestrial globe or to measure its 
dimensions ; the human race would believe it in- 
habited a more or less undulating plane. Optical 
instruments would never have been invented, ex- 
cept, perhaps, those of microscopy. We should 
err concerning the very foundations of our exist- 
ence, and we could never obtain any true knowl- 
edge of the earth's position, of the laws that gov- 
ern celestial motion, of the exterior universe, of 
space, of the infinite. The strangest and most 
ridiculous systems of philosophy and religion 
would flourish like weeds beneath this impenetra- 
ble fog, and human intelligence would probably 
always remain earthbound from inability to rise 
above an inferior condition. Or a slight differ- 
ence in the constitution of the atmosphere, in its 

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humidity, in its temperature, would suffice to con- 
demn us to a prison. What is a cloud ? What is 
fog ? Humid air become opaque. It is only a 
matter of proportion. A breath, a mere nothing, 
and we should be creatures of the meanest 
intelligence, lost in the lowest depths of ignor- 
ance. 

Men who have not thought much upon the sub- 
ject are always astonished when they hear it stated 
that astronomy is the first and most important of all 
the sciences. Nevertheless, there is proof of it. 
Astronomy is preeminently the most comprehen- 
sive science, the one which makes the universe 
known to us — our world and the others, time and 
space — which touches very closely the great prob- 
lems of universal life, the destiny of the soul, the 
infinite and the eternal. What an impetus to 
thought for even the most indifferent and uninter- 
ested minds ! Astronomy is the true light of 
human intelligence. Without it we dwell in a 
cave and all our conclusions concerning the crea- 
tion are false. This is a scientific and philosoph- 
ical truth whose importance we can never too 
fully appreciate. 

If astronomy is the most important science 
from the philosophical as well as from the purely 
scientific standpoint, the study of the heavens is 
also the sublimest of pursuits. It is evening. 
The sun has set in the clear, western sky at the 
close of a warm summer day ; the air, refreshed, 

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Five Weeks' Study of Astronomy 

is swept by a gentle breeze sweet with the 
fragrance of mown meadows ; restful silence fol- 
lows upon the noise and tumult of the day. 
Earth, lulled to sleep, allows the heavens to reign 
in their magnificence. The crescent moon hangs 
in the western sky like a celestial bark descend- 
ing toward another world. The stars begin to 
glow, one by one, in the transparent ether ac- 
cording to their brilliancy and position ; one by 
one we recognize Vega, white and clear, Arc- 
turus with golden rays, the seven stars of Ursa 
Major, the square of Pegasus, Andromeda, the 
radiant Capella rising slowly out of the northern 
mist. Slowly the constellations are traced and 
our eyes travel among those outlines in the 
heavens, upon which so many eyes have rested 
since the Chaldean shepherds were guided by 
the stars on their journey, and Job, Homer, and 
Hesiod sang of the Pleiades. And reflecting 
upon those mortal eyes, sightless today, which 
have gazed upon these same undying luminous 
points as brilliant now as in other days, we are 
impressed by the tremendous difference which sep : 
arates the earth from the heaven with its vast- 
ness, its duration, in the face of which our life is 
but a fleeting shadow ; and we are conscious of a 
certain nobleness which comes from the contem- 
plation of its immensity. 

Among these celestial lights we distinguish 
certain ones which shine with a calmer and 



(07) 



The Booklovers Reading Club 

less scintillating lustre, and yet seem to be more 
distended, as if these astral bodies were larger 
than the stars. Indeed Jupiter, Venus, and Mars 
appear, at times, immense. If we are familiar with 
even elementary astronomy we know there is 
a great difference between stars and planets ; 
the former are at remote distances, to us almost 
infinite, and are self-luminous, veritable suns in 
boundless space ; the latter are much nearer and 
form part of our own group, the solar system, and 
would not be visible but that they are illumined 
by the sun's light. Take, for instance, Jupiter, 
which at this time we are admiring in the constel- 
lation Sagittarius. Its distance is 626,000,000 
kilometres when it is, relatively to us, in opposi- 
tion to the sun. Not far from Jupiter, in the 
same constellation, Saturn shines with a dimmer 
light. Its distance is 1,172,000,000 kilometres. 
Undoubtedly these numbers seem large, but what 
are they in comparison with the distances of the 
fixed stars ? The nearest star to us, Alpha in 
Centaur, is enthroned in space at a distance esti- 
mated to be 41,000,000,000,000 kilometres; the 
second nearest, whose distance has likewise been 
measured — the sixty-first star in Cygnus — lies at 
68,000,000,000,000 kilometres ; the third, Sirius, 
is at 92,000,000,000,000 kilometres. The others 
are at a hundred, two hundred, three hundred tril- 
lions of kilometres — figures so large that they are 
inconceivable. We shall better understand the 



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Five Weeks' Study of Astronomy 



difference between planetary and stellar dis- 
tances if we estimate it by the time required for 
their light to reach us. Everybody knows the 
velocity of light, which flies through space like 
an arrow, or to put it better, like lightning, at the 
rate of 300,000 kilometres a second. Very well 
then, the ray of light which takes thirty-six 
minutes to reach us from Jupiter, and sixty- 
eight from Saturn, must travel four years in order 
to traverse the distance from the nearest fixed 
star, seven and a half from the sixty-first star in 
Cygnus, almost ten from Sirius, twenty-one from 
Vega, thirty-four from Arcturus, fifty, a hundred 
and more from the greater number of stars, and 
even thousands of years from others, flying all 
the time with the unvarying velocity of 300,000 
kilometres a second. In regard to space itself — 
it is without bounds. A telegram sent today 
addressed to the frontiers of heaven would never 
reach there. 

We can understand that the astronomer, ob- 
serving the preeminence of Jupiter, Saturn, Mars, 
or Venus in a constellation, believes he can almost 
touch them, so to speak. They are hundreds of 
thousands of times nearer to us than the stars. The 
astronomer lives in a sort of intimacy with these 
neighboring worlds, because the telescope magni- 
fies them perceptibly, and discloses certain details 
of surface and physical constitution. On the 
other hand, the stars are so infinitely remote that 



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The Booklovers Reading Club 



they never appear but as luminous points, even 
with the aid of the strongest telescopic appliances. 
Saturn reveals its marvelous rings and its eight 
satellites. Jupiter sails along accompanied by its 
train of four enormous satellites (to this number 
a fifth and minute one has recently been added 
through the discovery of an American, Mr. Bar- 
nard), and in its diurnal rotation discloses its 
cloudy aspects, its belts, both dark and bright, 
drawn from east to west. Jupiter's varying phases 
suggest that beneath its hot, thick atmosphere 
there is in process of formation a world covered 
with clouds and vapors, a world whose surface is 
as restless as that of an immense ocean. Mars, 
from its appearance, may be an inhabited world 
with seasons similar to our own in severity and 
twice as long, with polar snows melting in sum- 
mer and accumulating in winter, with continents, 
oceans, or vast vegetating, swampy plains, with 
canals regularly intersecting its immense areas, 
and with strange topographical features which 
impress us as belonging to a world full of activity 
and apparently inhabited by a race superior to 
our own. 

How can we study these other worlds without 
finding our ideas tremendously enlarged ; without 
seeing the earth grow small and lose itself, as it 
were, in the unimportant place to which nature has 
assigned it ; without being sure that our globe 
does not constitute the entire universe, but is only 



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Five Weeks' Study of Astronomy 

an unimportant part of a vast whole, a small 
province, an ant-hill ; without feeling that our 
existence is but a passing phase in universal and 
everlasting life ? 

If the study of the heavens is a mysterious de- 
light to the mind, if astronomy is the science 
which teaches us more than any other, it is, as 
well, the best of meditations. Astronomy shows 
us what is small in that which we believed great, 
transitory in that which we believed permanent, 
contingent in that which we believed absolute ; it 
asks us to believe that our seeming loneliness in 
the heart of the sidereal universe is not a real iso- 
lation, but that a real relationship binds all the 
worlds, that these unknown races are our kin- 
dred, and that an infinite solidarity governs the 
universe. Our horizon is enlarged. We feel 
that we are not inhabitants of a country or even 
of a planet, but are citizens of heaven by the 
same right as would be ours if we lived upon 
some other orb of the solar system, or of the 
countless stellar systems lost in the starry deeps. 

One of my readers recently wrote me a letter 
contesting the conclusion of an article whose final 
argument was that astronomy improves our moral 
nature, enlarges our ideas, enlightens our con- 
sciences, and elevates our souls. I quote from his 
letter the following statements: "Of course, if 
we were all astronomers the world would be more 
peaceful. But the facts do not prove at all that 

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The Booklovers Reading Club 

^mmmmBmmimmmtamm^*mmm^aa^mmtmiaama*t-Taamx^iimitB*mwMxxscmmam*kamammrmmmtmmmmimmmtmmammmwmmm^mmmm^ 

science makes man better. Dr. Lapommerais, 
Eyraud, Ciampi, and Prado certainly could not 
have been ignorant of the fact that the earth is 
a planet revolving around the sun, and must 
even have known other facts ; but that did not 
prevent them from becoming superlative scoun- 
drels." 

It is not futile to reply to these remarks, for 
they are not the only ones of their kind ; indeed, 
it is common enough to hear them seriously ad- 
vanced by certain people. Undoubtedly, knowl- 
edge and morality do not necessarily go hand in 
hand. It is possible to find extremely well edu- 
cated men who are thieves and even assassins. 
But who does not feel, judging impartially, that 
scientific pursuits keep the mind in a serene and 
peaceful condition, remote from the brutal in- 
stincts of animal existence, and that in these there 
is a safeguard for society ? Moreover, it is not 
of knowledge, of education strictly speaking, that 
I wished to talk, but of the scientific and, more 
particularly, the astronomical spirit. I am re- 
proached for asserting that Dr. Lapommerais, an 
assassin because of his love of money, must have 
known that the earth is a planet revolving around 
the sun. I admit his knowledge of the fact ; but 
what does that prove ? It is not enough to know 
a thing ; it must be felt and understood. A mem- 
orable saying of long ago runs, ''The letter 
killeth, the spirit maketh alive." If we pause on 

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Five Weeks' Study of Astronomy 

the surface we cannot penetrate the hidden depths. 
I insist that he cannot be a bad man who is ani- 
mated by the philosophical spirit of astronomy, 
f Let us listen for an instant to the voice of 
heaven. The infinite surrounds us on all sides. 
Each star in boundless space is a sun radiating 
in its own vicinity waves of light, heat, and elec- 
tricity. The globe we inhabit belongs to a little 
system of one star, our sun. The universe ap- 
pears as endless and unbounded space, peopled 
with myriads of worlds, some of them in embryo, 
some inhabited and in every stage of intellectual 
development, some dead ; and we feel that the 
epoch in which we live is of no special importance 
and is not superior to those which have preceded 
or those which will follow ours, that the entire 
human race passes like a shadow, and that this 
planet is but an infinitesimal representative in the 
assembly of worlds. Our terrestrial human spe- 
cies seems to our eyes, like its planetary abode, 
commonplace and imperfect ; but with all its im- 
perfection and wretchedness it appears to be 
gradually progressing by evolution in the unques- 
tionable advance of knowledge and ability. 
(Furthermore, we now understand that a man's 
true value does not consist in the fortune 
he may have inherited from his ancestors, in a 
certain particle or title before his name, in the 
social position he may occupy, in his dress, in any 
external decoration he may wear, but solely in his 

(73) 



The Booklovers Reading Club 

moral and intellectual worth. We have the same 
feelings and opinions in regard to the greatness 
of nations, and we estimate their value by intel- 
lectual, not material, power. 

Just one hundred years ago France and her 
military chief were governing the Continent. 
Where are they today ? Yet what are a hundred 
years in the history of the human race ! One 
moment, one fleeting instant swiftly gone. Were 
rulers inspired by the philosophical spirit of astron- 
omy the Chinese would not have been robbed, 
pillaged, and assassinated in their own country, 
and the fields of South Africa would not have 
been stained with the blood of Boers and English. 
We are barbarians and fools, mistaking appear- 
ances for realities ; we are just as much slaves as 
men were in the days when Etienne de la Boetie 
wrote his fine treatise upon Voluntary Servitude. 

Men animated with the spirit of astronomy 
could never be fools, slaves, or barbarians. They 
never would have made the mistake of revoking 
the edict of Nantes, of planning the massacre 
of Saint Bartholomew, of guillotining Lavoisier, 
Bailly, Andre Chenier, Fabre d' Eglantine, and 
other honest men. Astronomical philosophy is a 
torch that can never become a devastating fire. 
You may reply that all the sciences, and particu- 
larly astronomy, are not for the world in general. 
This is a mistake. One may be an astronomer in 
this philosophical sense, just as one may be a 

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Five Weeks' Study of Astronomy 

Catholic, a Protestant, an Israelite, a Mussulman, 
or a Buddhist ; it is only necessary to understand 
the elementary astronomical facts, to learn the 
essential truths of this sublime science, to know 
the relative position of the earth and its part in 
the rhythmical harmony of creation. Bad instincts 
cannot germinate in such a soil. One will laugh 
at vanity and ambition, at wealth and human folly ; 
one will live in a pure and quiet atmosphere, tak- 
ing advantage of no man, either by abusing his 
credulity or by imposing upon him the yoke of 
servitude. Such men still form a minority. 
Politicians are not among them. 

The true and the good are branches of the 
same tree. No science, no line of thought, places 
us face to face with truth as does astronomy ; none 
puts us so closely in touch with the infinite. 
If in the silence of midnight our soul has been 
borne upward toward the starry shores of the 
Milky Way ; if it has seen, as in a vision, our 
errant planet revolving with its sisters around the 
sun, the sun itself sailing away into the starry 
desert ; if it has understood that space is bound- 
less, that traveling for a hundred thousand years 
with the velocity of light could not advance us a 
single step into its endlessness ; if it has felt but 
once the awe of infinity and eternity ; then it has 
seen the history of nations recede like a billow 
and lose itself in nothingness ; it has looked in 
vain for the conquests of Alexander and the Pha- 

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The Booklovers Reading Club 

raohs, the empires of Augustus and Charlemagne ; 
it has been present at the gradual dissolution of 
ambitious dreams ; it has seen idols with feet of 
clay crumbling one by one : and nothing remains 
but spirit, but truth ascertained, but the conquests 
of thought. Among all the vanquished nations, 
one alone shines as an unfading star — little 
Greece, the tiny archipelago in the blue sea, the 
land of Homer, Pythagoras, Plato, and Phidias, 
the land of the beautiful, the good, and the true, 
whose brightness the proudest empire of modern 
times has never obscured. The man who is 
thrilled by these imaginings, these thoughts, these 
convictions, sees in mankind a single family ; in 
boundaries, arbitrary and harmful divisions ; in 
all history, a single purpose — the advancement of 
thought. This scientific philosophy is superior 
to all creeds, all religions, is untouched and unfet- 
tered by material interests, and its adepts live in 
light, in truth, and in harmony. 



Cdt<^^££ /^£^c^« 




(76) 



How to Make a Sun-Dial : 
A Practical Suggestion by 

HAROLD JACOBY 



\n) 



How to Make a Sun-Dial : 
A Practical Suggestion by 

HAROLD JACOBY 



Dr. Harold Jacoby received his degree from 
Columbia College in 1885, and has been professor 
of astronomy at Columbia since 1894. He is the 
author of numerous papers on astronomical pho- 
tography, stellar parallax, and star clusters, 
which have been published in the journals of 
scientific societies of Paris, London, St. Peters- 
burg, and New York. His less technical papers 
appear from time to time in the New York Even- 
ing Post, the Boston Transcript, and various 
magazines. Dr. Jacoby was a member of the 
United States eclipse expedition (1889-90) to 
West Africa. He belongs to several professional 
organizations in Europe and America, and is 
corresponding secretary of the New York 
Academy of Sciences. He contributed the section 
on astronomy to The International Year Book, 
1 898- 1 900. 

The question is often asked : Why is it desir- 
able to study astronomy ? Would it not be 
better to devote our time to something less 
abstruse, less far away — in short, to something 
practical that we can use in our everyday life? 
There must exist a good answer to this question, 
just as there must be a reason why students of 
early human records accept the state of astro- 
nomical knowledge as a touchstone by which to 
test the intellectual development of ancient 

(79) 



The Booklovers Reading Club 

peoples. What is there, then, about astronomy 
distinguishing that science among all branches of 
human learning ? On the one hand, it makes an 
appeal to the imagination, almost invariably irre- 
sistible ; for no mind remains unaffected by the 
vastness inseparable from the heavens. This 
gives us a poetry of the stars, attractive above and 
beyond the science itself. Joined to this, again, 
is another characteristic still more important. 
The problems of astronomy are the most intricate 
known to the intellect of man, and yet they are 
the ones permitting the most exact solutions. 
Astronomy has been rightly called the "perfect 
science ;" but its perfection does not consist in 
completeness of knowledge. It is not that our 
information is all gathered in, that no chance of 
further success tempts men on to new fields of 
research, but that the harvest we hope to gain in 
the future, like those garnered in the past, will be 
quite perfect of its kind. 

It is a singular thing, then, that astronomy, 
though a leader among the more abstruse sci- 
ences, should, nevertheless, be the one that comes 
nearest to the people in their daily life. For it 
is to astronomy that we owe the possibility of 
regulating time and navigating ships. Without 
the results of observatory work we could neither 
guide vessels across the ocean nor adjust the time- 
pieces used in our everyday affairs. 

In the present article we propose to explain 

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Five Weeks' Study of Astronomy 

briefly how to construct one of the earliest time- 
measuring devices, the sun-dial. It is always 
better in studying science to do something our- 
selves rather than merely talk about the dis- 
coveries of others. Unfortunately, in astronomy 
observational work of the highest interest is closed 
to the amateur on account of the lack of costly 
instruments and observatories ; and theoretical re- 




searches generally require as a pre-requisite too 
considerable a knowledge of pure mathematics. 
The construction of a simple instrument like the 
sun-dial, however, is possible to everyone and 
will stimulate a further interest in astronomical 
study. 

Figure i shows what a sun-dial should look like. 
The lines to show the shadow's place at the 
different hours of the day are marked on the 



6l 



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The Booklovers Reading Club 



board A B C D, and this is put on some horizon- 
tal flat surface, such as a window-sill or piazza 
floor. The three-cornered piece of board a b c y 
which is called the Gnomon, is fastened to the 
bottom board A B C D by screws going through 
A B C D from underneath. The edge a b of the 
three-cornered board a b c casts the shadow which 
marks the hours of the day. Of course, it is 
important that this edge should be straight and 
perfectly flat and even. Any one handy with tools 
can make it quite easily, but it is just as satisfac- 
tory to mark the right shape on a piece of paper 
very carefully, and take it to a carpenter, who 
can cut the board according to the pattern marked 
on the paper. 

Figure 2 shows how to draw the shape of the 
three-cornered board a b c. The side a c should 
always be just five inches long. 
The side b c is drawn at right 
angles to a c, which can be 
done with an ordinary carpen- 
ter's square. The length of b c 
depends on the place for which 
-sin.-- — c t h e d} a i i s ma de. The following 
FIG - 2 table gives the length of b c 

for various cities in the United States. After 
the length of b c has been marked out, it is 
merely necessary to complete the three-cornered 
piece by drawing the side a b from a to b: 




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Five Weeks' Study of Astronomy 



TABLE SHOWING THE LENGTH OF THE SIDE t C 



Place Inches 





4 u-i6 










Buffalo 




Charleston 


.... 31-4 














Detroit 

Indianapolis 


4 1-2 

4 1-16 








3 11-16 


New Orleans . . . . 


2 7-3 



New York 438 

Omaha . 4 3S 

Philadelphia 4 3-16. 

Pittsburg 4 3-8 

Portland, Me 4 13-16 

Richmond 3 15-16 

Rochester 4 11-16 

San Diego 3 1-4 

San Francisco 3 15-16 

Savannah 31-8 

St. Louis 3 15-16 

St. Paul s 

Seattle 5 9-16 

Washington, D.C 4 1-16 



If it is desired to make a dial for a place not 
given in the table, it will be near enough to use 
the distance b c as given for the place nearest to 
you. But in selecting the nearest place from the 
table, it is important to take that one of the cities 
mentioned which is nearest in a north-and-south 
direction. It does not matter how far away the 
place is in an east-and-west direction. So instead 
of taking the place that is nearest on the map in 
a straight line, take the place to which one could 
travel by going principally east or west, and very 
little north or south. The figure is drawn about 
the right shape for New York. The board used 
for the three-cornered piece should be about one- 
half inch thick. But if a window-sill dial is being 
made, it may be preferable to have it smaller 
than that described here. It can be made half as 
big by taking all the sizes and lines in half inches 
where the table calls for inches. 



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The Booklovers Reading Club 



After marking out the dimensions for the three- 
cornered piece that is to throw the shadow, you 
can prepare the dial itself, with the lines that show 
the place of the shadow for every hour of the 
day. This you can do in the manner shown in 
fig. 3. Just as in the case of the three-cornered 
piece, the dial can be drawn with a pencil di- 



X X! XII I II 




kio. 3 



D 



rectly on a smooth piece of white board, about 
three quarters of an inch thick, or marked out on 
a paper pattern and transferred afterward to the 
board. Perhaps it will be as well to begin by 
drawing on paper, as any mistakes can then be 
corrected before commencing to mark the wood. 
In the first place you must draw a couple of 
lines M n and m' n', eight inches long and just far 



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Five Weeks' Study of Astronomy 



enough apart to fit the edge of the three-cornered 
shadow piece. Since that was to be one-half 
inch thick, the two lines will also be one-half inch 
apart. Now draw the two lines N o and n' o' 
square with m n and m' n', and make the distances 
n o and n' o' just five inches each. The lines o k, 
o' k', and the other lines forming the outer border 
of the dial, are drawn just as shown, o k and o' k' 
being each eight inches long, the same as m n and 
m' n'. The lower lines in the figure, which are 
not very important, are to comp]ete the squares. 
The lines n o and n' o' must be marked with the 
number vi, these being the lines reached by the 
shadow at six o'clock in the morning and evening. 
The points where the vn, viii, and other hour 
lines cut the lines o k, o' k', m k and m' k' can be 
found from the following table. (Page 86.) 

In using the table it will be noticed that the line 
ix falls sometimes on one side of the corner k and 
sometimes on the other. Thus for Albany the 
line passes seven and seven-sixteenths inches 
from o, while for Charleston it passes four and 
three-eighths inches from m. For Baltimore it 
passes exactly through the corner k. 

The distance for the line marked v from o' is 
just the same as the distance from o to vn. Simi- 
larly, iv corresponds to viii, in to ix, n to x, and 
i to xi. The number xn is marked at m m', as 
shown. If we desire to add lines (not shown in 
fig. 3 to avoid confusion) for hours earlier than 



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The Booklovers Reading Club 

six in the morning, it is merely necessary to mark 
off a distance on the line k o, below the point o, 
and equal to the distance from o to vn. This 
will give the point where the 5 a. m. shadow line 
drawn from n cuts the line k o. A correspond- 

TABLE SHOWING HOW TO MARK THE HOUR LINES 



Place 



Albany 

Baltimore .... 

Boston 

Buffalo 

Charleston .... 

Chicago 

Cincinnati .... 
Cleveland .... 

Denver 

Detroit 

Indianapolis . . . 
Kansas City . . . 
Louisville .... 
Milwaukee .... 
New Orleans . . . 
New York .... 

Omaha 

Philadelphia . . . 

Pittsburg 

Portland, Me. . . 
Richmond .... 
Rochester .... 
San Diego .... 
San Francisco . . 
Savannah .... 

St. Louis 

St. Paul 

Seattle 

Washington, D. C. 



Distance from O 
to the line marked 



Inches 

1 15-16 

2 1-8 
2 

1 15-16 

2 7-16 



1-8 

1-8 

1-8 

i-4 

i-4 

15-16 

11-16 



15-16 
i-4 

15-16 
7-16 
1-4 
9-16 
i-4 

15-16 

13-16 
1-8 



Inches 

4 3-i6 
4 11-16 
4 5-i6 

4 3-i6 

5 3-8 
4 5-i6 
4 11-16 
4 5-i6 
4 1-2 
4 5-i6 
4 11-16 



16 
1-16 
3-i6 
3-4 
5-16 
5-i6 
1-2 
5-i6 
3-16 
1-16 

4 3-i6 

5 3-8 

4 11-16 

5 9-i6 
4 11-16 
4 1-16 

3 15-16 

4 11-16 



Inches 

7 7-i6 
8 

7 7-i6 

7 7-i6 

7 7-i6 

8 

7 7-i6 

7 11-16 

7 7-i6 

8 

8 

8 

7 7-i6 

7 11-16 
7 11-16 
7 11-16 
7 11-16 
7 1-8 
8 
7 7-i6 



7 1-8 
6 5-8 



Distance from M 


to the line marked 


IX 


, » 


Inches 


Inches 


Inches 




3 1-16 


1 7-16 




2 7-8 


1 7-16 




3 1-16 


1 7-16 




3 1-16 


1 7-16 


4 3-8 


2 1-2 


1 1-8 




3 1-16 


1 7-16 




2 7-8 


1 7-16 




3 1-16 


1 7-1 6 




2 7-8 


1 7-16 




3 1-16 


1 7-16 




2 7-8 


1 7-16 




2 7-8 


1 5-16 




2 7-8 


1 5-16 




3 1-16 


1 7-16 


4 1-16 


2 5-16 


1 1-8 




3 1-16 


1 7-16 




3 1-16 


1 7-16 




2 7-8 


1 7-16 




3 1-16 


1 7-16 




3 3-i6 


1 1-2 




2 7-8 


1 5-i6 




3 1-16 


1 7-16 


4 3-8 


2 1-2 


1 1-8 




2 7-8 


1 5-16 


4 i-4 


2 1-2 


1 1-8 




2 7-8 


1 5-16 




3 3-i6 


1 1-2 




3 3-8 


1 1-2 




2 7-8 


1 7-16 



ing line for 7 p. m. can be drawn from n' on the 
other side of the dial. 

After you have marked out the dial very care- 
fully, fasten the three-cornered shadow piece to it 
in such a way that the whole instrument will look 



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Five Weeks' Study of Astronomy 

like fig. i. The edge a c (fig. 2) goes on n m 
(fig. 3). The point a (fig. 2) must come exactly 
on n (fig. 3); and as the lines n m (fig. 3) and 
n'm' (hg. 3) have been made just the right dis- 
tance apart to fit the thickness of the three-cor- 
nered piece a b c (fig. 2), everything will go to- 
gether just right. The point c (fig. 2) will not 
quite reach to M (fig. 3), but will be on the line 
n m (fig. 3) at a distance of three inches from m. 
The two pieces of wood will be fastened together 
with three screws going through the bottom 
board a b c d (figs. 1 and 3) and into the edge 
a c (fig. 2) of the three-cornered piece. The 
whole instrument will then look something like 
fig. 1. 

After your sun-dial has been thus put together, 
it is merely necessary to set it in the sun in a 
level place, on a piazza or window-sill, and turn 
it round until it tells the right time by the shadow. 
Local time can be obtained from a watch near 
enough for setting up the dial. Once set right 
you can screw it down or mark its position, and 
it will continue to give solar time every day in the 
year. 

If it is desired to adjust the dial very closely, 
you must go out some fine day and note the error 
of the dial by a watch at about ten in the morn- 
ing, and at noon, and again at about two in the 
afternoon. If the error is the same each time, 
the dial is rightly set. If not, turning the dial 

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slightly will make it possible to get the three 
errors nearly the same. When they are as nearly 
alike as possible, the dial will be sufficiently near 
right. The solar or dial time may, however, dif- 
fer somewhat from ordinary watch time, but the 
difference will never be great enough to be very 
serious, nor will it accumulate and increase from 
day to day, like the error of an imperfect clock. 




In response to our invitation to contribute an article to this 
course Dr. Jacoby suggested that we reprint the foregoing paper, 
which he had prepared for the Cosmopolitan Magazine (April, 
1900). The article has been partly re-written for the present pub- 
lication. 



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Illustrative Selections 



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Illustrative Selections 



EARLY ASTRONOMICAL VIEWS 

Agues M. Clerke 
Until nearly a hundred years ago the stars were 
regarded by practical astronomers mainly as a 
number of convenient fixed points by which the 
motions of the various members of the solar sys- 
tem could be determined and compared. Their 
recognised function, in fact, was that of milestones 
on the great celestial highway traversed by the 
planets, as well as on the byways of space occa- 
sionally pursued by comets. Not that curiosity as 
to their nature, and even conjecture as to their 
origin, were at any period absent. Both were 
from time to time powerfully stimulated by the 
appearance of startling novelties in a region de- 
scribed by philosophers as "incorruptible," or 
exempt from change. The catalogue of Hippar- 
chus, probably, and certainly that of Tycho Brahe, 
some seventeen centuries later, owed each its 
origin to the temporary blaze of a new star. The 
general aspect of the skies was thus (however 
imperfectly) recorded from age to age, and with 
improved appliances the enumeration was ren- 
dered more and more accurate and complete ; 
but the secrets of the stellar sphere remained 
inviolate. 



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THE IDEAL ASTRONOMER 

Herbert A. Howe 

His nervous system is well developed, his eye- 
sight and hearing are fair, and his sense of touch 
is delicate. His hand is steady under trying cir- 
cumstances. Nervousness is not a bane of his 
life, causing him to lose control of himself at 
moments when every faculty must be at its best, 
and every muscle obedient to his behest. 

When observing a transit of Venus, a repeti- 
tion of which will not occur during his lifetime, he 
is, at the critical instants, as cool and collected as 
if sitting in his office, looking over a new book. 
This self-control comes from long training; it 
finds a parallel in the steadiness with which a 
surgeon's hand, though previously trembling, 
executes the crucial part of a difficult operation, 
when the life of the patient hangs in the balance, 
This ability to exercise self-control is enhanced 
by the astronomer's plain living and regular 
habits. 

It is a mistake to suppose that he is ordinarily 
at work at all hours of the night, and tucks in bits 
of sleep partly by day and partly by night, under 
the direction of an alarm clock. For the majority 
of nights are cloudy, so that no observing is done ; 
when the weather is clear he usually has on hand 
some work which comes during a certain portion 
of the night. He rarely works all night. Comet 
hunters are exceptions in the matter of regularity. 



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They change their times of observing from night 
to night, working generally during those hours 
when the moon is below the horizon ; the faint 
objects which they discover are not commonly 
readily visible in moonlight. 

Astronomers are, on the whole, well educated 
men, especially those who are the directors of large 
observatories. Very little can be done in their 
science without a sound knowledge of elementary 
mathematics. The principles of physics and 
mechanics come up continually. An American 
astronomer who cannot read scientific German 
and French with considerable ease is often ser- 
iously hampered in his work ; for he must master 
the contents of many publications in those lan- 
guages. Often he wishes to read Italian ; a 
knowledge of Latin and Greek is not infre- 
quently of service. 

An astronomer may be very narrow-minded. 
The ceaseless round of computation by day and 
observation by night, demanding every iota of his 
time, has a strong tendency to keep his mind 
from expanding along any other lines. But if, as 
usual, he has been through an old-fashioned, now 
much berated, college curriculum, the liberalizing 
effect of the four years of study of various 
branches of knowledge keeps him from undue 
narrowness. It is noteworthy that men of only 
moderate mental caliber are the most likely to 
shrivel up. The mental giants have a many- 



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The Booklovers Reading Club 

sidedness, which leads them to explore other 
realms of knowledge to a moderate extent. One 
of the best text-books on political economy pub- 
lished in this country is the work of an astrono- 
mer, most of whose time is occupied with direct- 
ing intricate calculations belonging to the strictly 
mathematical side of the science. 

The director of a large observatory is continu- 
ally brought into contact with men who are prom- 
inent in other lines of scientific work, and with 
those who have won success in various non- 
scientific walks of life. He also looks after the 
business interests of the observatory, and some- 
times raises funds for the enlargement of its 
work. These circumstances effectually prevent 
his becoming a recluse. 

THE EVOLUTION OF THE EARTH 

Camille Flammarion 
During thousands of centuries the terrestrial 
globe rolled through space in the condition of a 
great chemical laboratory. A perpetual deluge 
of boiling water fell from the clouds upon the 
burning soil, and rose in vapour in the atmosphere, 
again to fall. When the temperature became 
lower than that of boiling water, the vapour lique- 
fied and was precipitated. In the midst of these 
frightful tempests the terrestrial crust, broken 
open a thousand times by the convulsions of the 

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Five Weeks' Study of Astronomy 

central fire, vomited out flames, and closed again. 
The first lands which emerged from the universal 
ocean were islets of arid and sterile granite. 
Later on, from the bosom of the waves, the first 
semi-fluid combinations of carbon formed the 
earliest rudimentary attempts at life, protoplasm, 
a substance which scarcely merits the name of 
organism, which is no longer a simple mineral, 
but is still neither vegetable nor animal. The 
primitive plants, the seaweeds, which float inert in 
the ocean, were already in progress. The primi- 
tive animals, the zoophytes, elementary molluscs, 
corals, medusas, were also progressing. Imper- 
ceptibly, age by age the planet loses its rough- 
ness, the conditions of life are improved, beings 
multiply and become different from the primitive 
stock, acquiring organs, at first rough and rudi- 
mentary, afterwards developed and perfected. 

The primeval age, in which the new-born life 
was represented by the seaweeds, Crustacea, and 
vertebrates still destitute of a head, seems to have 
occupied alone 53 hundredths of the time which 
has elapsed since the earth became habitable. 

The primary period which succeeded it had for 
its type the establishment of the coal vegetation 
and the reign of fishes, and appears to have occu- 
pied the following 31 hundredths. 

The secondary period, during which the splen- 
did coniferous vegetation ruled the vegetable 
world, while enormous saurian reptiles dominated 

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the animal world, lasted for the following 12 hun- 
dredths. The earth was then peopled with fan- 
tastic beings, devoting themselves to perpetual 
combats in the midst of ungovernable elements. 

We have here, then, according to the compara- 
tive thickness of the geological formations which 
have been deposited in these successive epochs, 
96 hundredths of past time occupied by a living 
nature absolutely different from that which now 
embellishes our globe, a nature relatively formida- 
ble and coarse, and as distinct from what we know 
as that of another world. Who would have then 
dared to raise the mysterious veil of futurity 
and divine the future unknown epoch when, by a 
new transformation, Man should appear upon the 
planet ? 

The tertiary period, during which appeared only 
mammals and animal species, which show more or 
less physical affinity with the human species, 
came, then, to gather up the inheritance of the 
primitive ages, and to substitute itself for the pre- 
ceding period. Its duration did not even reach 
three-hundredths of the total time. 

Finally, the quaternary age saw the birth of the 
human species, and of cultivated plants. It repre- 
sents but a hundredth of the scale of time, more 
probably half a hundredth. 

How these grand contemplations enlarge the 
ideas which we habitually form of nature ! We 
imagine that we go very far back in the past in 

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Five Weeks' Study of Astronomy 

contemplating the old pyramids still standing on 
the plains of Egypt, the obelisks engraved with 
mysterious hieroglyphics, the silent temples of 
Assyria, the ancient pagodas of India, the idols of 
Mexico and Peru, the time-honoured traditions of 
Asia and of the Aryans, our ancestors, the instru- 
ments of the stone age, the flint weapons, the 
arrows, the lances, the knives, the sling-stones of 
our primitive barbarism — we scarcely dare to 
speak often thousand, of twenty thousand years. 
But even if we admit a hundred thousand years 
for the age of our species, so slowly progressive, 
what is even this compared with the fabulous suc- 
cession of ages which have preceded us in the 
history of the planet ! 

In allotting one hundred thousand years to the 
quaternary age, the age of our present nature, 
we see that the tertiary period would have 
reigned during five hundred thousand years pre- 
viously, the secondary period during two millions 
three hundred thousand, the primary period during 
six millions four hundred thousand, and the prim- 
eval period during ten millions seven hundred 
thousand. Total : twenty millions of years ! And 
what is even this history of life compared with the 
total history of the globe, since it has taken more 
than three hundred millions of years to render 
the earth solid and to reduce its external tempera- 
ture to 20o° ? And how many millions must we 
still add to represent the time which elapsed be- 

7L (97) 



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tween the temperature of 200 and that of 70 , 
the probable maximum possible for organic life ! 

TIME AND ITS DISTRIBUTION 

Herbert A. Howe 

No endeavor is made to keep a standard clock 
right, for the constant changes which would be 
necessary would introduce intolerable disturb- 
ances into the clock's performance. It is therefore 
permitted to go on, month after month, without 
alteration, its errors and rates being determined 
from time to time by observations of the stars. 

We have seen how an astronomer gets time, 
and how he endeavors to keep it. We shall now 
see how he disseminates it for the benefit of the 
country at large. 

Here electricity comes into play ; as a telegraph 
operator by touching his key can make any 
sounder on the line tick, so a clock may be 
arranged to accomplish the same end. While 
the second-hand is flying from one second to the 
next one, a tooth of a wheel mounted on the same 
arbor as the second-hand strikes a miniature tele- 
graph key, and the signal is sent. One of the 
clocks at the United States Naval Observatory at 
Washington sends a signal over the Western 
Union wires to distant cities day after day, and 
thousands of telegraphic instruments tick as the 
signal passes. 

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Five Weeks' Study of Astronomy 



The sending of the signal is but a small part of 
the work of disseminating the time. In some 
cities a time ball is hoisted to the top of a pole a 
few minutes before noon and released at noon by 
an electrical impulse. In others the fire bells are 
rung- at the same hour. The Western Union 
Telegraph Company controls a system of clocks, 
which are set automatically once a day when a 
signal is sent to them. Thus a business man may 
have reasonably correct time in his office, if he is 
willing to pay the small rental charged by the 
company. The system conduces to the accurate 
running of trains, for every important railway 
station contains a telegraph office. 

The system of standard meridians, which has 
been adopted by the railroads and by the most im- 
portant municipalities, is a great convenience. 
The trains in the eastern portion of the United 
States are governed by Eastern Standard time, 
which is five hours later than Greenwich time, and 
is not far from local time at Philadelphia. Cen- 
tral Standard time is six hours later than Green- 
wich time, and is used in the Mississippi Valley 
and adjacent states. It is nearly the same as 
local time at St. Louis. Mountain time differs 
from Greenwich time by seven hours and domi- 
nates the semi-arid region formerly known as the 
Great American Desert. The seven-hour merid- 
ian passes through Denver. Pacific time, one 
hour slower still, is the standard for the Pacific 



I f A ^9) 

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coast. The eight-hour meridian passes centrally 
through California. 

Two further improvements upon this plan may 
yet be made. There should be no insurmounta- 
ble difficulty in having the time the same through- 
out any given state. The fact that the meridian 
by which Central time is governed runs near the 
Mississippi River much facilitates the grouping of 
the states in such a way that the time which 
should be adopted in each one is easily remem- 
bered. 

A further desirable change, which would be 
more difficult of accomplishment, because of the 
conservatism of even so progressive a people as 
Americans, is counting the hours continuously 
through the day from one to twenty-four. The 
designations, a. m. and p. m., would then be 
unnecessary. This system has already been tried 
upon the Canadian Pacific Railway, and is in force 
in Italy. Its advantages are simplicity and accu- 
racy. Astronomers already have a twenty-four- 
hour day, which begins at noon. 

The business man prefers to have the date 
change at midnight, when he is usually asleep. 
The astronomer finds it inconvenient to change 
the date at midnight, when he is frequently en- 
gaged in observation. The astronomical day 
begins twelve hours later than the civil day ; Jan- 
uary 5, io a.m., is January 4, 22 hours, by astro- 
nomical reckoning. March 16, 8 p.m., is March 16, 

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Five Weeks' Study of Astronomy 

8 hours, astronomically reckoned. Astronomers 
have of late years discussed the advisability of 
making their day begin at the same time as the 
civil day, viz., at midnight, but they have not yet 
made the change. 

Europe is much in advance of America in the 
matter of time distribution. The city of Paris is 
supplied with a system of electrical clocks, and 
also with a system of pneumatic clocks, which, as 
their name indicates, are driven by compressed 
air. The standard clocks are so numerous that 
any one may learn the time accurately with little 
trouble. Many small municipalities have exten- 
sive systems of electrical dials. 

One of the most elaborate systems of time dis- 
tribution is to be found in Great Britain. The 
Royal Observatory at Greenwich is the source of 
accurate time, which is telegraphed over the 
United Kingdom. A time ball is dropped at 
Greenwich for the use of ships in the Thames. 
Another at Deal serves the shipping in the 
Downs. The great clock at Westminster Palace 
is regulated in accordance with the telegraphic 
signals. Through the post-office department are 
sent signals which are utilized in various ways, 
such as the regulation of clocks, the striking of 
bells, and the firing of cruns. 



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— aaaMMiiM nn im i h i iiiii.i i ii i — i m ■ 'i n iaii rrmn -aer— i— ■ ■«■ »■ «iiii m m juummmn-imji n !■■■— i 

SPECTRUM GRATINGS 

Agnes M. Clerke 

Of many ingenious improvements in spectro- 
scopic appliances the most fundamentally import- 
ant relate to what are known as "gratings." 

These are very finely striated surfaces by which 
light-waves are brought to interfere, and are thus 
sifted out, strictly according to their different 
lengths, into " normal " spectra. Since no uni- 
versally valid measures can be made in any 
others, their production is quite indispensable to 
spectroscopic science. Fraunhofer, who initiated 
the study of the diffraction spectrum, used a real 
grating of very fine wires ; but rulings on glass 
were adopted by his successors, and were by 
Nobert executed with such consummate skill that 
a single square inch of surface was made to con- 
tain 100,000 hand-drawn lines. Such rare and 
costly triumphs of art, however, found their way 
into very few hands, and practical availability was 
first given to this kind of instrument by the 
inventiveness and mechanical dexterity of two 
American investigators. Both Rutherfurd's and 
Rowland's gratings are machine-ruled, and reflect, 
instead of transmitting the rays they analyse ; but 
Rowland's present to them a very much larger 
dirTractive surface, and consequently possess a 
higher resolving power. The first preliminary to 
his improvements was the production, in 1882, of 
a faultless screw, those previously in use having 

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Five Weeks' Study of Astronomy 

been the inevitable source of periodical errors in 
striation, giving, in their turn, ghost-lines as 
subjects of spectroscopic study. Their abolition 
was not one of Rowland's least achievements. 
With his perfected machine a metallic area of 6% 
by \Y^ inches can be ruled with exquisite accuracy 
to almost any degree of fineness; he considers, 
however, 43,000 lines to the inch to be the limit 
of usefulness. The ruled surface is moreover 
concave, and hence brings the spectrum to a 
focus without a telescope. A slit and an eye- 
piece are alone needed to view it, and absorption 
of light by glass lenses is obviated — an advantage 
especially sensible in dealing with the ultra- or 
infra-visible rays. 

STELLAR SPACES 

C ami lie Flammarion 
In forming an idea of the immensity of the 
desert which surrounds our solar system some 
comparisons will be more easily grasped than the 
figures themselves. Representing by 1 yard 
the distance which separates us from the sun, and 
placing the sun at the centre of the system, that 
globe would be one-third of an inch in diameter, 
our planet would be quite a small point of -^^ of 
an inch in diameter, placed at 1 yard, and Nep- 
tune, the frontier of our planetary republic, would 
be a ball of ^V of an inch placed at ninety-eight 
feet. To mark the distance of the nearest star, 



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it should be removed to 170 miles, or from Paris 
to beyond Brussels ; such is the proportion be- 
tween the extent of the solar system and inter- 
stellar immensity. There, the first sun met with 
would be represented by a sphere of a size similar 
to that which we have supposed for our sun. 

Let us suppose that a celestial traveller were 
carried out in space by a motion of such rapidity 
that he would in twenty-four hours pass over the 
distance which extends from the sun to Neptune 
(more than two thousand millions of miles). This 
velocity is so enormous that we would cross the 
Atlantic from Havre to New York in less than the 
tenth of a second. Our traveler would in forty- 
eight minutes pass over the space extending from 
the sun to the earth, and would arrive at Neptune 
at the end of the first day. But, having thus 
traversed the whole system, he would still travel 
in a straight line and with the same velocity for 
twenty-five years before reaching the first star, 
and he would then have the same voyage before 
him to arrive at the second, and so on. The earth 
would have disappeared from his view in the middle 
of the first day, and all the planets would have 
vanished before the end of the third day ; then 
the sun himselt, gradually diminishing in bright- 
ness, would year by year sink to the rank of a 
star. 

We have remarked above that if we could 
throw a bridge from here to the sun, this celestial 



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Five Weeks' Study of Astronomy 

bridge would be composed of eleven thousand 
six hundred arches as wide as the earth. Sup- 
pose a pillar at each extremity of this bridge. It 
would be necessary to repeat this same bridge 
tivo hundred and seventy-five thousand times to 
reach the nearest sun ; that is to say, this marvel 
of imaginary architecture, more wonderful than 
all the fables of ancient mythology, and more 
fabulous than all the tales of The Thousand ajid 
One Nights, would be composed of 275,000 
piers, distant from each other by 93 millions of 
miles. 

A star, a sun, may cause an explosion. If the 
noise of such a terrible conflagration could be 
transmitted to us, we should not hear it till the 
end of tliree million seven htcndred and ninety-five 
thousand years ! 

We may add, further, that an express train 
which, at the constant velocity of 37 miles an hour, 
would pass over in 266 years the space which 
separates us from the sun, would not arrive at the 
nearest star, Alpha Centauri, until after an unin- 
terrupted run of nearly seventy-three millions of 
years ! 

The sphere of the sun's attraction extends 
through the whole of space out to infinity. To 
speak accurately and minutely, there is not in the 
whole universe any particle of matter which does 
not feel to some extent the attractive influence of 
the sun, and even that of the earth, and of all 



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other bodies still lighter ; each atom in the uni- 
verse has an influence on every other atom, and in 
displacing objects on the surface of the earth — 
in sending a ship from Marseilles to the Red 
Sea — we disturb the moon in its course. But, as 
we have seen, the action is in the direct ratio of 
the masses and in the inverse ratio of the square 
of the distances. The influence of the sun on the 
stars is not only excessively small with reference 
to the velocity of motion which it would produce 
in a given interval of time, but there is here only 
the influence of one star among its equals. On 
all sides, moreover, the reign of the sun is limited, 
for there are innumerable suns in all directions, 
and the sphere ruled by each star is as limited as 
that of our own star, so that everywhere we 
should find regions where his influence would be 
neutralised. 

The sphere of the sun's attraction extends, 
nevertheless, out to and beyond the distance of 
Neptune. Strictly speaking, it extends indefi- 
nitely out to points where, in various directions, 
it meets with spheres of attraction of the same 

intensity. 

JUL 

COMETS AND PLANETS 

Camille Flammarion 

Four principal characteristics distinguish 

comets from planets: (i) their nebulous aspect 

and their tails, often considerable ; (2) the length 

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Five Weeks' Study of Astronomy 



of the elliptical orbits which they describe ; (3) 
the inclination of these orbits, which, instead of 
lying in the plane of the ecliptic, or at least in the 
zodiac, like those of the planets in general, are 
inclined at all degrees up to a right angle, and 
sometimes carry the comets to the polar constella- 
tions ; (4) the directions of their motions, which, 
instead of being performed in the same direction 
as those of planets, are, some direct, others retro- 
grade, and appear to be strangers to any unity of 
plan. From these circumstances the certain con- 
clusion follows that comets have not the same 
origin as the planets, that they did not originally 
belong to the solar system, that they travel 
through immensity, that they may be transported 
from one sun to another, from star to star, and 
that those which revolve round our sun have been 
caught in their passage by his attraction, having 
had their course curved and closed by the influ- 
ence of the planets of our system. 

THE NEBULAR HYPOTHESIS 

Agnes M. Clerke 

We cannot doubt that the solar system, as we 
see it, is the result of some process of growth — 
that, during innumerable ages, the forces of Nature 
were at work upon its materials, blindly modeling 
them into the shape appointed for them from the 
beginning by Omnipotent Wisdom. To set our- 
selves to inquire what that process was, may be 

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an audacity, but it is a legitimate, nay, an inevita- 
ble one. For man's implanted instinct to " look 
before and after" does not apply to his own little 
life alone, but regards the whole history of crea- 
tion, from the highest to the lowest — from the 
microscopic germ of an alga or a fungus to the 
visible frame and furniture of the heavens. 

Kant considered that the inquiry into the mode 
of origin of the w r orld was one of the easiest 
problems set by Nature ; but it cannot be said that 
his own solution of it was a satisfactory one. He, 
however, struck out in 1755 a track which thought 
still pursues. In his Allgemeine Naturgeschichte 
the growth of sun and planets was traced from 
the cradle of a vast and formless mass of evenly 
diffused particles, and the uniformity of their 
movements was sought to be accounted for by the 
uniform action of attractive and repulsive forces, 
under the dominion of which their development 
was carried forward. 

In its modern form, the " Nebular Hypothesis" 
made its appearance in 1 796. It was presented by 
Laplace with diffidence, as a speculation unfortified 
by numerical buttresses of any kind, yet with 
visible exultation in having-, as he thought, 
penetrated the birth-secret of our system. He 
demanded, indeed, more in the way of postulates 
than Kant had done. He started with a sun ready 
made, and surrounded with a vast glowing atmos- 
phere, extending into space out beyond the orbit 

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Five Weeks' Study of Astronomy 

of the farthest planet, and endowed with a slow 
rotatory motion. As this atmosphere or nebula 
cooled, it contracted ; and as it contracted, its 
rotation, by a well-known mechanical law, became 
accelerated. At last, a point arrived when tan- 
gential velocity at the equator increased beyond 
the power of gravity to control, and equilibrium 
was restored by the separation of a nebulous ring 
revolving in the same period as the generating 
mass. After a time, the ring broke up into frag- 
ments, all eventually reunited in a single revolving 
and rotating body. This was the first and farthest 
planet. 

Meanwhile the parent nebula continued to 
shrink and whirl quicker and quicker, passing, as 
it did so, through successive crises of instability, 
each resulting in, and terminated by, the formation 
of a planet, at a smaller distance from the centre, 
and with a shorter period of revolution than its 
predecessor. In these secondary bodies the same 
process was repeated on a reduced scale, the birth 
of satellites ensuing upon their contraction, or not, 
according to circumstances. Saturn's ring, it was 
added, afforded a striking confirmation of the 
theory of annular separation, and appeared to 
have survived in its original form in order to throw 
light on the genesis of the whole solar system ; 
while the four first discovered asteroids offered an 
example in which the debris of a shattered ring 
had failed to coalesce into a single globe. 

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This scheme of cosmical evolution was a char- 
acteristic bequest from the eighteenth century to 
the nineteenth. It possessed the self-sufficing 
symmetry and entireness appropriate to the ideas 
of a time of renovation, when the complexity of 
nature was little accounted of in comparison with 
the imperious orderliness of the thoughts of man. 
Since it was propounded, however, knowledge 
has transgressed many boundaries, and set at 
naught much ingenious theorising. How has it 
fared with Laplace's sketch of the origin of the 
world ? It has at least not been discarded as 
effete. The groundwork of speculation on the 
subject is still furnished by it. It is, nevertheless, 
admittedly inadequate. Of much that exists it 
gives no account, or an erroneous one. The march 
of events certainly did not everywhere — even if 
it did anywhere — follow the exact path prescribed 
for it. Yet modern science attempts to supplement, 
but scarcely ventures to supersede it. . . . 

But recent science raises many objections to 
the details, if it supplies some degree of con- 
firmation to the fundamental idea of Laplace's 
cosmogony. The detection of the retrograde 
movement of Neptune's satellite made it plain 
that the anomalous conditions of the Uranian 
world were due to no extraordinary disturbance, 
but to a systematic variety of arrangement at the 
outskirts of the solar domain. So that, were a 



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trans-Neptunian planet discovered, we should be 
fully prepared to find it rotating, and surrounded 
by satellites circulating from east to west. The 
uniformity of movement, upon the probabilities 
connected with which the French geometer mainly 
based his scheme, thus at once vanishes. 

The excessively rapid revolution of the inner 
Martian moon is a further stumbling-block. On 
Laplace's view, no satellite can revolve in a shorter 
time than its primary rotates ; for in its period of 
circulation survives the period of rotation of the 
parent mass which filled the sphere of its orbit 
at the time of giving it birth. And rotation 
quickens as contraction goes on ; therefore, the 
older time of axial rotation should invariably be 
the longer. This obstacle can, however, it seems, 
be turned. 

More serious is one connected with the plan- 
etary periods, pointed out by Babinet in 1861. 
In order to make them fit in with the hypothesis 
of successive separation from a rotating and con- 
tracting body, certain arbitrary assumptions have 
to be made of fluctuations in the distribution of 
the matter forming that body at the various epochs 
of separation. Such expedients usually merit the 
distrust which they inspire. 

Again, it was objected by Professor Kirkwood 
in 1869 that there could be no sufficient cohesion 
in such an enormously diffused mass as the planets 
are supposed to have sprung from, to account for 

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the wide intervals between them. The matter 
separated through the growing excess of cen- 
trifugal speed, would have been cast off, not by 
rarely recurring efforts, but continually, fragmen- 
tarily, pari passu, with condensation and accelera- 
tion. Each wisp of nebula, as it found itself 
unduly hurried, would have declared its inde- 
pendence, and set about revolving and condensing 
on its own account. The result would have been 
a meteoric, not a planetary system. 

Moreover, it is a question whether the relative 
ages of the planets do not follow an order just the 
reverse of that concluded by Laplace. Professor 
Newcomb holds the opinion that the rings which 
eventually constituted the planets divided from 
the main body of the nebula almost simultaneously, 
priority, if there were any, being on the side of 
the inner and smaller ones ; while in M. Faye's 
cosmogony, the retrograde motion of the systems 
formed by the two outer planets is ascribed — on 
grounds, it is true, of dubious validity — to their 
comparatively late origin. 

This ingenious scheme is designed, not merely 
to complete, but to supersede that of Laplace, 
which, undoubtedly, through the inclusion by our 
system of oppositely directed rotations, forfeits 
its claim simply and singly to account for the 
fundamental peculiarities of its structure. 

M. Faye's leading contention is that, under the 
circumstances assumed by Laplace, not the two 

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Five Weeks' Study of Astronomy 



outer planets alone, but the whole company, must 
have been possessed of retrograde rotation. For 
they were formed — ex hypothesi — after the sun ; 
central condensation had reached an advanced 
stage when the rings they were derived from 
separated ; the principle of inverse squares con- 
sequently held good, and Kepler's laws were in 
full operation. Now particles circulating in obe- 
dience to these laws can only — since their velocity 
decreases outward from the centre of attraction — 
coalesce into a globe with a backward axial move- 
ment. Nor was Laplace blind to this flaw in his 
theory ; but his effort to remove it, though it 
passed muster for the best part of a century, was 
scarcely successful. His planet-forming rings were 
made to rotate all in one piece, their outer parts 
thus necessarily traveling at a swifter linear rate 
than their inner parts, and eventually uniting, 
equally of necessity, into 3. forward- spinning body. 
The strength of cohesion involved may, however, 
safely be called impossible, especially when it is 
considered that nebulous materials were in ques- 
tion. . . . 

In one form or another, if we speculate at all 
on the development of the planetary system, our 
speculations are driven into conformity with the 
broad lines of the Nebular Hypothesis — so far, at 
least, as admitting an original material unity and 
motive uniformity. But we can see now, better 

8l (113) 



The Booklovers Reading Club 

than formerly, that these supply a bare and im- 
perfect sketch of the truth. We should err 
gravely were we to suppose it possible to recon- 
struct, with the help of any knowledge our race 
is ever likely to possess, the real and complete 
history of our admirable system. " The subtlety 
of nature," Bacon says, "transcends in many ways 
the subtlety of the intellect and senses of man." 
By no mere barren formula of evolution, indis- 
criminately applied all round, the results we 
marvel at, and by a fragment of which our life is 
conditioned, were brought forth ; but by the mani- 
fold play of interacting forces, variously modified 
and variously prevailing, according to the local 
requirements of the design they were appointed 
to execute. 



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Stimulative Sluestions 




he questions which follow 
bear upon the topics of 
the course as presented 
in the handbook. 'They 
aim to stimulate further 
research as well as to test the amount of 
information gained. Full and thought- 
ful answers, written out if possible, 
will greatly assist in changing transitory 
impressions into permanent ones, and 
will make a fixed point of departure for 
further study. 



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STIMULATIVE QUESTIONS 



i. Give approximately the time when each of the 
following named men lived, and the thing for which 
each is best known to astronomers : Hipparchus, Ptol- 
emy, Copernicus, Tycho Brahe, Kepler, Galileo, New- 
ton, Laplace, William Herschel, Halley, Fraunhofer, 
Adams, Leverrier. 

2. Name the discoveries of the past century which 
seem to you to have done the most to advance our 
knowledge of the heavenly bodies. 

3. What is the meaning of each of the following 
terms : horizon, celestial pole, zenith, nadir, latitude, 
longitude, ecliptic, zodiac, altitude, azimuth, declination, 
right ascension ? 

4. Is the earth a perfect sphere? If not, by how 
much does it differ from a perfect sphere ? Is there 
any reason why it should not be a perfect ellipsoid of 
revolution ? What is an ellipsoid of revolution ? 

5. Captain Slocum, in his account of his voyage alone 
around the world, says that many of the eminent men 
among the Boers believe the earth to be flat, and that 
they so maintained in conversation with him. By what 
arguments could you persuade an intelligent person of 
the truth ? 

6. Why is there a difference between the length of 
the sidereal day and that of the day by the sun-dial ? 

7. Do you ever see the sun directly overhead ? 

8. As you look at the Pole Star on a summer even- 
ing, on which side is the Great Dipper ? 

9. Did you ever see Jupiter and the Great Dipper at 
the same time without turning the eyes? 

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The Booklovers Reading Club 

io. Can the sun ever shine in at a north window ? 
Give a reason for your answer. 

11. Why is it possible to see the sun when it is actu- 
ally just below the horizon? 

12. What is meant by mean solar time? 

* 13. What is the Gregorian calendar? What is the 
meaning of "old style" applied to a date of one hundred 
and fifty years ago ? 

14. What is the shape of the earth's orbit ? 

15. What is meant by aphelion and perihelion ? 

16. What is precession? 

17. What is meant by the phases of the moon ? How 
do you explain them ? 

18. How much of the moon's surface do we ever see ? 
Why do we not see more ? 

19. Did you ever see an eclipse of the moon ? If so, 
you probably saw the whole surface of the moon through- 
out the eclipse. Explain this and the red color. 

20. Why do we not have an eclipse of the moon and 
an eclipse of the sun every month ? 

21. Name the planets in their order from the sun. 

22. Have you ever seen Mercury ? Why is it not 
more often seen ? 

23. Describe the appearance of the planet Venus at its 
brightest. Where would you look for it ? 

24. How does Jupiter appear as seen through your 
glass ? If you have seen any of his satellites, describe 
their appearance also. 

25. Give some estimate of the brilliancy of the sun's 
surface. 



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Five Weeks' Study of Astronomy 



26. What is supposed to be the condition of the sun ? 

27. How is the sun's supply of heat kept up ? 

28. What is a sun-spot, and what is believed to be its 
cause ? 

29. How has the constitution of the sun been deter- 
mined ? 

30. What are meant by the corona and the promi- 
nences ? What are the prominences supposed to be ? 

31. Explain the production of tides. What is meant 
by tidal friction ? 

32. What has been the effect of tidal friction in the 
past in the case of the earth and the moon ? 

33. Describe the fundamental differences between a 
reflecting and a refracting telescope. Name the advan- 
tages and the disadvantages of each form. 

34. W T hat is gained by using a large aperture in a tele- 
scope ? 

35. Why are the great telescopes made so long ? 

36. Name the great telescopes of the world. 

37. What is the use of a " transit circle " or " meridian 
circle ? " 

38. Give a brief description of the spectroscope. What 
does it tell us ? 

39. What is " parallax ? " 

40. How are the distances of the stars and planets 
determined ? 

41. How are the masses of the heavenly bodies de- 
termined ? 

42. Describe the relations of the bodies known to be- 
long to the solar system. 

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The Booklovers Reading Club 

43. What is the appearance of the surface of Mercury 
so far as it is known ? 

44. Why is the length of Mercury's day the same as 
that of its year, and why has it probably no satellite ? 

45. What appear to be the characteristics of the at- 
mosphere of Venus ? 

46. Sketch briefly the history of the moon. 

47. Sketch briefly the history of the earth and its 
probable future. 

48. Describe the prominent formations on the moon's 
surface as seen through your glass. 

49. What is the general appearance of the planet 
Mars ? 

50. What do we know about the canals of Mars ? 

51. What are believed to be the conditions prevailing 
on Mars as to land, water, and atmosphere ? 

52. What reasons are there for believing that Mars 
cannot be inhabited by beings like ourselves ? 

53. How many satellites has Mars, and what peculiar- 
ities do they show ? 

54. What are the asteroids, and what are the theories 
in regard to their origin ? 

55. Describe the appearance of Jupiter as seen through 
a powerful telescope. 

56. How does Jupiter compare, in mass and size, with 
the earth ? 

57. What is supposed to be the condition of Jupiter ? 

58. How many moons has Jupiter ? 

59. Describe the appearance of Saturn. 

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Five Weeks' Study of Astronomy 

60. Of what do Saturn's rings consist ? Why must 
this be the case ? 

61. What is supposed to be the condition of Saturn? 

62. What is likely to be the complete history of the 
rings of Saturn ? 

63. How many satellites has Saturn, and how do they 
compare in size with our own moon ? 

64. What is the most striking peculiarity of the sys- 
tem of Uranus ? 

65. What is probably the condition of Uranus ? 

66. State briefly what is known of Neptune. 

67. Give the history of the discovery of Neptune. 

68. Name the two most remarkable comets of the past 
century. 

69. What is believed to be the origin of the tails of 
comets ? 

70. What is supposed to be the origin of meteors ? 

71. Name six of the familiar bright stars and tell 
where to look for them. 

72. How many stars can you count in the Pleiades ? 

73. About what is the distance of the nearest star ? 

74. How are the stars designated ? 

75. Toward what point is the solar system moving, 
and how is it determined ? 

76. What are binary stars ? 

77. How may the speed of a star in the line of sight 
be determined ? 

78. State briefly Laplace's theory of the formation of 
the solar system. 

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Topics for Special Papers 
d for Open Discussion 



an 



1. The naming of the constellations. 

2. Famous astronomers. 

3. The systems of Ptolemy and Copernicus. 

4. Newton's work for astronomy. 

5. Tides and their influence in the formation of sat- 
ellites. 

6. The harvest moon. 

7. Topography of the moon. 

8. The making of great telescopes. 

9. The spectroscope's story of the stars. 

10. Reflectors vs. refractors. 

11. Celestial photography. 

12. The formation of the solar system. 

13. What are sun-spots ? 

14. The future of Saturn. 

15. The life of a comet. 

16. Variable stars. 

17. Structure of the heavens. 

18. Meteoritic and regenerative hypotheses of the 
sun's heat. 

19. Is the sun growing hotter or colder ? 

20. Is Mars inhabited ? 

21. Is Venus inhabited ? 

22. The origin of the asteroids. 

23. What is the cause of the brightness of comets' 
tails ? 



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Supplementary Reading 

Recommended for this course by 

PROFESSOR C. A. YOUNG 

i. A Popular History of Astronomy dur- 
ing the Nineteenth Century. By Agnes 

M. Clerke. 

A book of great interest, recommended highly by 

Professor Young. It is complete and accurate, yet 

simple and straightforward, so that one not especially 

versed in astronomy can read it with interest and 

profit. 

2. The Story of the Heavens. By Robert 

Stawell Ball. 

A careful study of the whole field of astronomy for 
average readers. It is profusely illustrated, many of 
the plates being colored. "All Sir Robert Ball's 
books are well written and interesting, and he knows 
his subjects so that there are seldom any blunders of 
fact or statement in his pages." — Professor Young. 

3. Popular Astronomy : A General De- 
scription of the Heavens. By Camille Flam- 
marion. 

Translated from the French by J. E. Gore. A very 
comprehensive and elaborate book, fully illustrated. 
It is distinctively popular in its object. 

4. A Text-book of Astronomy. By George 

C. Comstock. 

A good, careful text-book. The author "has en- 
deavored to concentrate attention upon those parts 

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The Booklovers Reading Club 

of the subject that possess special educational value.'* 
Directions are given for observations with simple 
apparatus. It does not attempt to cover the entire 
field of astronomy. 

5- A Study of the Sky. By Herbert A. Howe. 
A book for beginners. It is simple and accurate. 
Helpful for locating the constellations, and fixing the 
elementary lore of the subject. 

6. Elements of Astronomy. By Simon New- 
comb. " It is very good and may be safely taken as 
authoritative as far as it goes." — Professor Young. 



Modesty forbade Professor Young to name two books which 
we are unwilling to om it. We therefore add the following : 

7- The Sun. By C. A. Young. 

Professor Young's book is recognized as the final 
authority on the subject it treats. It is not a popu- 
lar book, though it is simple and straightforward in 
its style. 

s. General Astronomy. By C. A. Young. 

An excellent text-book for the serious student. 



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Twenty-Five Reading Courses 



No. i— PROBLEMS IN MODERN DEMOCRACY 

Among the contributors to the handbook accompanying this 
course are ex-President Cleveland; Woodrow Wilson, Professor 
of Politics, Princeton University ; Henry J. Ford, author of Rise 
and Growth of American Politics; and Henry D. Lloyd, author 
of Newest England. The books for the course are selected 
by Mr. Cleveland. 

No. 2— MODERN MASTERS OF MUSIC 

Among the contributors to the handbook accompanying this 
course are Reginald de Koven, Dr. W. S. B. Mathews, editor of 
Music ; James G. Huneker, editor of Musical Courier ; Henry 
E. Krehbiel, musical critic New York Tribune; and Gustave 
Kobbe, author of Wagner s Life and Works. The most attrac- 
tive reading course ever offered to lovers of music. 

No. 3— RAMBLINGS AMONG ART CENTRES 

Among the contributors to the handbook accompanying this 
course are F. Hopkinson Smith, Dr. John C. Van Dyke, Dr. 
John La Farge, President of the Society of American Artists ; 
Kenyon Cox and Dr. Russell Sturgis. The handbook is 
attractively illustrated. Mr. Smith and Dr. Van Dyke are 
responsible for selecting the books to be read. 

No. 4— AMERICAN VACATIONS IN EUROPE 

This course is the next best thing to going abroad oneself. 
Among the contributors to the handbook are Frank R. Stockton, 
Jeannette L. Gilder, editor of The Critic; Mrs. Schuyler Crown- 
inshield and George Ade. The handbook has a fine portrait 
frontispiece. 

No. 5— A STUDY OF SIX NEW ENGLAND CLASSICS 

The books for this course are selected by Dr. Edward 
Everett Hale. Among the contributors to the handbook are 
Dr. Hale, Julian Hawthorne, Mrs. James T. Fields and Dr. 
Edward Waldo Emerson. Dr. Emerson is a son of Ralph Waldo 
Emerson. This is one of the most attractive courses in the 
entire series. 

No. 6- SHAKESPEARE'S ENGLISH KINGS 

The plays are selected for this course by H. Beerbohm 
Tree, the well-known English actor, and the books to be read 
in connection with the plays are selected by Sir Henry 

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The Booklovers Reading Club 



Irving. Among the other contributors to the handbook are Prof. 
Edward Dowden, acknowledged the greatest Shakespearean 
scholar of Great Britain, Dr. Hiram Corson, of Cornell Univer- 
sity; Dr. William J. Rolfe and Dr. Hamilton W. Mabie. The 
handbook is very attractively illustrated. 

No. 7— CHARLES DICKENS : HIS LIFE AND WORK 

Among the contributors to the delightful handbook accompany- 
ing this course are George W. Cable, the well-known novelist; 
Irving Bacheller, author of Eben Holden; Andrew Lang, the 
distinguished English writer ; Amelia E. Barr, the novelist ; and 
James L. Hughes, author of Dickens as an Educator. The 
books to be read are selected by Mr. Cable and Mr. 
Bacheller. The handbook is beautifully illustrated. 

No. 8— CHILD STUDY FOR MOTHERS AND TEACHERS 

Among the contributors to the handbook accompanying this 
course are Margaret E. Sangster, Nora Archibald Smith, Anne 
Emilie Poulson, Charlotte Perkins Gilman, Lucy VVheelock 
and Kate Gannett Wells. Mrs. Sangster selects the books to be 
read. 

No. 9— INDUSTRIAL QUESTIONS OF THE DAY 

The following distinguished writers on economic problems 
contribute to the handbook accompanying this course : Presi- 
dent Jacob Gould Schurman, of Cornell University ; Jeremiah 
Whipple Jenks, Professor of Political Science, Cornell University ; 
Richard Theodore Ely, Director of the Scnool of Economics, 
Political Science and History, University of Wisconsin ; Sidney 
Webb, Lecturer London School of Economics and Political 
Science, Member London County Council ; and Carroll Davidson 
Wright, United States Commissioner of Labor. 

No. io— FLORENCE IN ART AND LITERATURE 

Among the contributors to the handbook accompanying this 
course are William Dean Howells, Dr. Russell Sturgis, Frank 
Preston Stearns, author of Midsummer of Italian Art, Life of 
Tintoretto, etc.; Dr. William Henry Goodyear, Curator Fine Arts 
Museum of Brooklyn Institute; and Lewis Frederick Pilcher, 
Professor of Art, Vassar College. The handbook has some 
attractive illustrations. 

No. ii— STUDIES OF EUROPEAN GOVERNMENTS 

The books have been selected specially for this course by the 
Rt. Hon. James Bryce, of the English House of Commons, and 
the Hon. Andrew D. White, United States Ambassador to Ger- 



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The Booklovers Reading Club 



many. Among the other contributors to the handbook are Jesse 
Macy, Professor of Constitutional History and Political Science, 
Iowa College; and John William Burgess, Professor of Political 
Science and Constitutional Law, and Dean of the Faculty of 
Political Science, Columbia University. 

No. 12— FAMOUS WOMEN OF THE RENAISSANCE 

Among the contributors to the handbook accompanying this 
course are Col. Thomas Wentworth Higginson, Margaret Deland 
and Charlotte Brewster Jordan. The handbook has several 
very interesting illustrations. 

No. 13— THE MODERN CITY AND ITS PROBLEMS 

Among the contributors to the handbook accompanying this 
course are Dr. Frederic W. Speirs ; Dr. Albert Shaw, editor 
of The Review of Reviews ; Bird S. Coler, Comptroller of the 
City of New York, author of Municipal Government ; and Charles 
J. Bonaparte, Chairman of the Executive Committee of the 
National Municipal League. The books are selected by Dr. 
Speirs. 

No. 14— STUDIES IN APPLIED ELECTRICITY 

This is without exception the most attractive and the most 
helpful reading course ever offered to students of electricity. 
Thomas A. Edison selects the books specially for these studies. 
Among the other contributors to the handbook are Dr. Edwin 
J. Houston, Dr. Elihu Thomson, Carl Hering, Ex-President of 
the American Institute of Electrical Engineers ; and Arthur V. 
Abbott, Chief Engineer of the Chicago Telephone Company. 

No. 15— FIVE WEEKS' STUDY OF ASTRONOMY 

Among the contributors to the handbook accompanying this 
course are Charles A. Young, Professor of Astronomy, Prince- 
ton University ; Sir Robert S. Ball, Professor of Astronomy, 
Cambridge University, and Director of Cambridge Observa- 
tory, England ; Camille Flammarion, founder of the As- 
tronomical Society of France, and author of Marvels of the 
Heavens, Astronomy, etc.; George C. Comstock, Director of 
Washburn Observatory, University of Wisconsin ; and Harold 
Jacoby, Professor of Astronomy, Columbia University. The 
study programme includes contributions from the most famous 
astronomers of England and France. 

No. 16— RECENT ENGLISH DRAMATISTS 

Lovers of the best modern dramas will find much pleasure in 
these studies. Among the contributors to the handbook are 
Brander Matthews, Professor of Literature, Columbia University; 

9 l (129) 



The Booklovers Reading Club 



Dr. William Winter, Dramatic Critic for the New York Tribune ; 
Dr. Harry Thurston Peck, Editor of The Bookman; Louise 
Chandler Moulton ; and Norman Hapgood, the well-known 
writer of dramatic criticism. The handbook has some interest- 
ing illustrations. 

No. 17— STUDIES IN CURRENT RELIGIOUS THOUGHT 

The books are chosen for the course by Dr. Lyman Abbott 
and Dr. Washington Gladden. Among the contributors to 
the handbook are Dr. Samuel D. McConnell, Rector of Holy 
Trinity Church, Brooklyn ; President William DeWitt Hyde, of 
Bowdoin College ; Dr. Amory H. Bradford, Editor of The 
Outlook ; Dr. Henry Collin Minton, of San Francisco Theological 
Seminary, late Moderator of the Presbyterian General Assembly ; 
Dr. H. W. Thomas, Pastor of the People's Church, Chicago; 
and Dr. Theodore T. Munger, Pastor of the United Congrega- 
tional Church, New Haven. For clergymen and laymen who 
wish to stimulate the growth of a theology which is in harmony 
with the best thought of the time we recommend this handbook 
and this reading course. 

No. 18— THE GREATER VICTORIAN POETS 

The books are selected for this course by Thomas Bailey 
Aldrich. Among the other contributors to the handbook are 
Thomas R. Lounsbury, Professor of English, Yale University; 
Dr. T. M. Parrott, of Princeton University ; and Marie Ada Moli- 
neux, author of The Phrase Book of Broivning. 

No. 19— OUT-OF-DOOR AMERICANS 

Among the contributors to the handbook accompanying this 
course are John Burroughs, Ernest Seton-Thompson, President 
David Starr Jordan, of the Leland Stanford Junior University ; 
Ernest Ingersoll and Hamlin Garland. Lovers of nature will 
find delight in the outlines and recommendations of this course. 

No. 20— THE WORLD'S GREAT WOMAN NOVELISTS 

Mrs. Humphry Ward, the well-known English novelist, is the 
first contributor to the handbook accompanying this course. 
The other contributors are Elizabeth Stuart Phelps Ward, Mary 
E. Wilkins, Agnes Repplier, Katherine Lee Bates, Professor of 
English, Wellesley College; and Oscar Fay Adams. The hand- 
book contains some interesting illustrations. 

No. 21— AMERICAN FOUNDATION HISTORY 

Hon. Henry Cabot Lodge selects the books for this course. 
Among the other contributors are Albert Bushnell Hart, Pro- 
fessor of American History, Harvard University ; John Bach 

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The Booklovers Reading Club 



McMaster, Professor of American History, University of Penn- 
sylvania ; Reuben Gold Thwaites, Secretary of the State Histori- 
cal Society of Wisconsin, author of The Colonies ; Paul Leicester 
Ford, author of Janice Meredith; and Andrew Cunningham 
McLaughlin, Professor of American History, University of 
Michigan. 

No. 22— STUDIES IN AMERICAN LITERARY LIFE 

Professor Barrett Wendell and Professor Lewis E. Gates, of 
Harvard, and Dr. Horace E. Scudder, late editor of The Atlantic 
Monthly, contribute to the handbook accompanying this course. 
For a brief stimulative and instructive course in American litera- 
ture nothing better could possibly be offered. 

No. 23— STUDIES IN RECENT FRENCH FICTION 

Alcee Fortier, Professor of Romance Languages, Tulane 
University of Louisiana, has chosen the books for this reading 
course. Among the contributors to the handbook are the three 
distinguished French writers, Edouard Rod, Ferdinand Bru- 
netiere and Paul Bourget, and the notable American critic, 
Dr. Benjamin W. Wells, author of Modern French Literature and 
A Century of French Literature. 

No. 24— THE ENGLISH BIBLE : HOW WE GOT IT 

The contributors to this course include President William R. 
Harper, of the University of Chicago ; John Franklin Genung, 
Professor of Rhetoric, Amherst College ; William Newton Clarke, 
Professor of Christian Theology, Colgate University; and Richard 
G. Moulton, Professor of English Literature, University of 
Chicago. The handbook is a very interesting and instructive 
volume in itself. 

No. 25— THE MECHANISM OF 

PRESENT DAY COMMERCE 

Ln Preparation. The books are selected by the Hon. Lyman 
]. Gage, Secretary of the Treasury. 



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V -OF C 



